The 2017 ATP World Tour season is past the halfway point and many of the big titles have already been decided. As the tour enters the back-half, one of the biggest storylines of every season begins to shift into the spotlight: the battle for the year-end number one ranking.

In some ways, 2017 has been one of the most unpredictable and stunning seasons on the ATP World Tour in recent memory. Because of this, two men are running away with the race to number one, but if 2017 has taught us anything, it’s that anything is possible.

Despite the fact that the battle for number one appears to be a two-horse race, there are still a maximum of 10,500 points still up for grabs for any player who could run the table. Here is a breakdown of what to look for and what to expect in the battle to end 2017 as the number one player in the world.

*Please note, for this discussion, the year-to-date rankings are being used, also known as the Race to London. These are not the same as the ATP Rankings, although the two will match at season’s end. The year-to-date rankings are shown below*

Ranking Player Points Point Back of #1
1. Rafael Nadal 7095 -
2. Roger Federer 6545 550
3.  Dominic Thiem 3345 3750
4.  Stan Wawrinka 3150 3945
5.  Marin Cilic 2905 4190
6.  Alexander Zverev 2710 4385
7. Novak Djokovic 2585 4510
8. Andy Murray 2290 4805
9. Grigor Dimitrov 1925 5170
10. Tomas Berdych 1905 5190

Front Runners

Historically, the player who finishes the year at number one was in the top two in the Race to London during the summer. That trend seems unlikely to change in 2017, as there is a wide gap between the top two in the race and the rest of the field. And with good reason as two men have been head-and-shoulders above the rest of the tour so far this season.

Rafael Nadal

Roland Garros champion and three-time former year-end number one Rafael Nadal currently sits in first in the year-to-date rankings with 7095 points. The Spaniard took the lead during the clay court season, which he dominated, winning all four of his 2017 titles on the dirt, including his record tenth French Open and two Masters 1000 titles. Despite a disappointing run at Wimbledon, the Spaniard has had a fantastic bounce-back year after an injury-ridden 2016 season. Of the eleven tournaments he’s played this year, Nadal has reached the quarterfinals or better at nine events.

Rafael Nadal bites his trophy at last month's French Open. Photo: Clive Brunskill/Getty Images
Rafael Nadal bites his trophy at last month's French Open. Photo: Clive Brunskill/Getty Images

The Spaniard is in good shape to make a charge to finish the season at number one for a fourth time, but he will face some challenges. First of all, his lead, which was as big as nearly 3000 points a month ago, has shrunk to 550 points. And the player behind him has dominated practically every event he’s played and is in a far stronger position to make a charge at number one.

The other challenge facing Nadal is that the remainder of the season is played on hard courts where the Spaniard has traditionally struggled. While Nadal has won each of the next three big events, the Rogers Cup, the Western and South Open, and the US Open, at least once each (three titles in Canada, one in Cincinnati, two in New York), his results tend to tail off as the season progresses. While the summer hard courts won’t be of too much concern, the post-US Open period will be a challenge. The Spaniard has only ever won three titles in the final two months of the season, with the last one coming in 2010.

Nadal celebrates a point during his fourth round match at Wimbledon. Photo: Michael Steele/Getty Images
Nadal celebrates a point during his fourth-round match at Wimbledon. Photo: Michael Steele/Getty Images

Nadal has often worn out in the Asian swing and on the European indoor hard courts. The Spaniard’s physical style of play tends to lead to exhaustion in the final months. As well, the court speed tends to increase in the final months, which doesn’t work well with Nadal’s game. However, Nadal has been in great form all year, even on hard courts. If he stays healthy, finishing at number one is a real possibility.  

Roger Federer

While Nadal may be (currently) the points leader in 2017, most would agree that Roger Federer is currently the best player in the world and has been all season. The Swiss has won two of the three majors and both Masters 1000 events that he entered. In fact, Federer has only two losses all season. He even held match points in both of those losses. He has not lost a match above the 500-level this season.

Federer currently sits 550 points behind Nadal in the year-to-date rankings, meaning he could take over first place as early as the Rogers Cup next month depending on the results. If Federer reached the final and Nadal lost in the first round, or Federer won the title and Nadal failed to reach the final, the Swiss would hop over him into the top spot. If Nadal outperforms the Swiss, he will widen the gap, making it harder for Federer to catch him.

Roger Federer holds his Wimbledon trophy. Photo: Clive Brunskill/Getty Images
Roger Federer holds his Wimbledon trophy. Photo: Clive Brunskill/Getty Images

Scheduling could play a huge role in Federer’s bid to reach number one. The Swiss often plays coy these days when discussing his schedule and is not afraid to skip events to protect his health, even if it costs him a shot at number one. For example, Federer is currently on the entry list for next month’s Rogers Cup in Montreal. However, the Swiss has only competed in Canada once in the last five years. It would not be surprising if he skipped it again this year to focus on Cincinnati, an event played the following week where he has had far more success.

Skipping Montreal could be dangerous, however, as it would give Nadal a free chance to stretch his lead. If Federer plays considerably fewer events than Nadal, it would seriously hurt his chances of finishing the year at number one for the first time since 2009.

That being said, Federer has been dominant in almost every event he’s played this year. That includes three victories over Nadal himself, meaning if the year-end number one came down to a head-to-head battle between Federer and Nadal, the Swiss would be the heavy favourite.

Federer and Nadal pose with their trophies after the Swiss was victorious in the Australian Open final. Photo: Scott Barbour/Getty Images
Federer and Nadal pose with their trophies after the Swiss was victorious in the Australian Open final. Photo: Scott Barbour/Getty Images

Federer is probably the favourite to finish the season at number one, not just because of how he’s played so far, but because of what events are still to be played. Unlike Nadal, the Swiss excels in the summer and post-US Open. He has won Cincinnati seven times, the US Open five times, and 21 total titles in the post-US Open period, including seven Basel titles, at least one title at each Masters 1000 title, and six year-end championship crowns. He is in a far better position to finish the season at number one.

He is a far-better hard court player than Nadal and is particularly good on the speedy courts of the US and indoors in Europe. Despite currently being in second, if Federer plays a full schedule and continues to play at even close to his early-2017 level, he is in prime position to finish at number one for the sixth time, which would tie Pete Sampras for the record for most years finished at number one.

Outside Dreamers

While Nadal and Federer are quite tightly packed at the top of the year-to-date rankings, there is a fairly large gap between them and the rest of the field. In fact, while Federer trails Nadal by very little, there is a large gap, over 3000 points, between number two Federer and third place Dominic Thiem. That’s three Masters 1000 titles or a major and Masters 1000 title’s worth of points just to close in on Federer. And that doesn’t include any points Federer or Nadal will gain themselves.

While it looks like it almost definitely will be either Federer or Nadal finishing the season at number one, it’s worth looking at the few men hoping to pull a miracle. After all, there are still a lot of points up for grabs.

Andy Murray

Andy Murray clinched the year-end number one ranking by winning the ATP World Tour Finals last year. Photo: Julian Finney/Getty Images
Andy Murray clinched the year-end number one ranking by winning the ATP World Tour Finals last year. Photo: Julian Finney/Getty Images

The 2016 year-end number one is facing an extremely uphill battle if he hopes to finish a second consecutive year at number one. Current world number one Andy Murray taught the world in 2016 that you can never count anyone out in the battle for the year-end number one, as he was over 3000 points back of first place Novak Djokovic in June of last year, only to catch the Serbian and finish the season at number one (although he had cut that deficit down to under 1000 points by this point in the season).

But Murray is facing far longer odds this year. The Scot is currently 4805 points behind Nadal for the top spot. If Murray won all four remaining Masters 1000 events, he would still trail Nadal by at least 805 points. Even if Murray won the US Open, he would still need to make up nearly 3000 more points on Nadal. And that is without even factoring in Nadal’s results. If Nadal reached the US Open final or the final of two of the remaining Masters 1000 events, all four Masters 1000 titles and the US Open would not be enough for Murray. At this point, even if Murray went undefeated for the rest of 2017, which he nearly did in 2016, that may not be enough. It’s probably too late for Andy Murray.

Murray limps along the baseline during his quarterfinal loss at Wimbledon. Photo: Clive Brunskill/Getty Images
Murray limps along the baseline during his quarterfinal loss at Wimbledon. Photo: Clive Brunskill/Getty Images

And then there is the issue of Murray. He is in this horrible position because he has had a horrible season. The Scot struggled with form for much of the season and now appears to be struggling with a hip injury. It is quite possible he could be forced to skip an event of two leading into the US Open to let his hip heal. If that happened, it would essentially kill his chances of finishing at number one. But even if Murray plays, he is a shadow of the man who finished the season at number one last year.

Novak Djokovic

Not only is Novak Djokovic’s streak of finishing the year in the top two at risk, it is looking like he may finish the season outside of the top three for the first time since 2006. The man who finished four of the last six seasons at number one is only in a marginally better position than Murray, sitting seventh in the year-to-date rankings, 4510 points back of Nadal for the top spot.

The math for Djokovic to reach number one is more or less the same as for Murray. He needs to be perfect. Nothing else would be sufficient. The good news for Djokovic is that the rest of the season is on hard courts, his best surface, and he’s won the Rogers Cup four times, the US Open twice, Shanghai and Paris three times each, and the year-end championships five times, so he knows that he can win at these venues.

Novak Djokovic receives medical treatment on his elbow during the Wimbledon quarterfinals. Photo: Julian Finney/Getty Images
Novak Djokovic receives medical treatment on his elbow during the Wimbledon quarterfinals. Photo: Julian Finney/Getty Images

Like Murray, however, Djokovic is having physical struggles. He was forced to withdraw down a set and a break during his quarterfinal match with Tomas Berdych at Wimbledon with an elbow injury. This injury has apparently bothered Djokovic for over a year now and also forced him to miss the Miami Open back in March. The Serbian has said that he is considering his options and may be forced to skip some events, which would kill his dream of reaching number one. Djokovic is extremely unlikely to challenge for the top spot in 2017.

Marin Cilic

The Wimbledon runner-up has thrown his name into the conversation after his great run at the All England Club. But like the rest of the challengers, Cilic is staring at a massive uphill fight. The Croatian sits just over 4000 points back of Nadal for the top spot. Cilic is erratic and asking for that amount of consistency from the Croatian is a big ask. While the surface does work well for him, he is the defending champion in Cincinnati and Basel and is a former US Open champion, too much consistency and big-match play is required for Cilic to reach the top

Dominic Thiem

Many people would likely be surprised to see that Dominic Thiem is currently third in the year-to-date ranking and has the smallest gap between himself and number one. The young Austrian has been extremely consistent throughout the season and has put up some solid results, including handing Rafael Nadal his lone loss of the clay court season.

Dominic Thiem celebrates his upset of Rafael Nadal in Rome. Photo: Gareth Copley/Getty Images
Dominic Thiem celebrates his upset of Rafael Nadal in Rome. Photo: Gareth Copley/Getty Images

However, even in third place, he sits 3750 points back of number one, meaning he’s going to need a lot of big titles to finish the year at number one. And big titles in something Thiem is lacking. He did reach the final in Madrid, losing to Nadal, but has otherwise struggled in the big tournaments, especially off of clay. He fell in the fourth round of both non-clay majors and his best showing at the Masters 1000 level on hard court was the quarterfinals of Indian Wells.

Thiem is probably a future French Open champion, but has yet to show that he has the game necessary to dominate the hard courts, which he would have to do to claim the year-end number one ranking. Worse still for Thiem’s chances are the fact that, at the four remaining Masters 1000 events combined in his entire career, he has only gotten past the second round once. Three or four big titles on the fast hard courts is asking a lot of the still-unproven Thiem.

Alexander Zverev

So far in 2017, three majors and five Masters 1000 events have been contested, a total of eight big events. Federer and Nadal have combined to win seven of them. The one exception was Alexander Zverev’s shocking triumph at the Italian Open. The win propelled Zverev to sixth in the year-to-date rankings, although he still sits 4385 points back of Nadal.

Alexander Zverev holds his Rome trophy after upsetting Novak Djokovic. Photo: Giuseppe Bellini/Getty Images
Alexander Zverev holds his Rome trophy after upsetting Novak Djokovic. Photo: Giuseppe Bellini/Getty Images

Zverev is only in his second full year on the ATP World Tour. While his results have been impressive, winning three titles, with the exception of Rome, he has yet to make a splash at the big events. He has yet to reach a major quarterfinal (his fourth round run at Wimbledon was the best of his career) and still seems to be a ways away from consistently winning big titles, something he would need to do to steal the year-end number one ranking. Zverev may be a future year-end number one, but 2017 is probably too soon.

Stan Wawrinka

Remember him? The French Open runner-up? The reigning US Open champion? There hasn’t been much talk about Stan Wawrinka this year. After a solid start to the season, the second Swiss has tailed off, with the notable exception of his run to the French Open final. He is currently fourth in the year-to-date rankings, 3945 points back of Nadal. Wawrinka is probably the most capable of challenging for the top spot. He is the only one of the chasers who has proven that he can win big titles and appears to be healthy.

Stan Wawrinka reacts to losing a point during the French Open final, which he lost to Rafael Nadal. Photo: Clive Brunskill/Getty Images
Stan Wawrinka reacts to losing a point during the French Open final, which he lost to Rafael Nadal. Photo: Clive Brunskill/Getty Images

That being said, consistent ability to win big titles has been the problem. He’s never reached more than one major final in a season and has never reached multiple Masters 1000 finals in a season. He needs to be far better and start playing at his championship level consistently if he wants to reach number one come November. Unlike the other close challengers, he has at least proven that he has a championship level.

Who Finishes at Number One

It will be Federer or Nadal. It is going to take an unprecedented run of historic proportions for anyone currently outside of the top two to finish the season at number one. Most of the chasers are young and unproven, injured, or have always struggled with inconsistency. And considering that anyone hoping to knock down Federer and Nadal would have to win at least three big titles to even make it close, that’s too much to ask. And that’s not including any points Federer and Nadal gain. The pair would each have to stop playing altogether for the final months of the season for anyone to have any chance of knocking them off.

Federer reacts to winning the Australian Open final earlier this year in his comeback tournament. Photo: Cameron Spencer/Getty Images
Federer reacts to winning the Australian Open final earlier this year in his comeback tournament. Photo: Cameron Spencer/Getty Images

So, it’s Federer vs. Nadal. The greatest rivalry in men’s tennis history is back at it as the two will do battle down the stretch for the coveted year-end number one ranking. This very well could come down to the wire, with the top spot going back and forth right up to the ATP Finals in November.

So who wins? The scales are tipping in Federer’s favour, as the surface is better for his game and overall, he appears to be in better form, especially on the hard courts. It is possible that the Swiss could skip some events and give Nadal some free points or his level could drop, but it looks like it is Federer race to win at the moment. Nadal will literally have to play the best summer and fall tennis of his career if he wants to hold off Federer.