Second seed Angelique Kerber had an easy passage into the second round of the US Open following the unfortunate withdrawal of Polona Hercog in her first match, however, the Australian Open champion had a tougher test with Mirjana Lucic-Baroni in the second round.
The German has a lot to play for at Flushing Meadows with the world number one ranking at stake, and she has the chance to a win a second Grand Slam singles title, however, Kerber survived a lapse of concentration in her second round match with Lucic-Baroni in the Louis Armstrong Stadium.
Kerber storms through the opening set
Lucic-Baroni began the opening set serving first, immediately found her under pressure in the first point of the match losing a nine shot rally with a forehand unforced error sailing into the net, however, after going 0-30 down, the Croat served an ace down the T at 109mph, followed by a forehand winner in a seven shot rally to make it 30-30.
Unfortunately, a couple of unforced errors handed Kerber the immediate break in the first game of the match.
It looked likely that Lucic-Baroni was going to break back gaining a 0-30 advantage on the German's serve but more unforced errors helped the second seed to consolidate the break at 2-0.
The world number 56 opened her second service game with a double-fault, and a forehand unforced error, but she got a game point with a couple of winners placed in the corner away from Kerber, however, the Australian Open champion's trademark forehand down the line had the Croat at the net, committing an unforced error into the net.
The game ebbed and flowed with winners and unforced errors, ultimately with Kerber creating her third break point opportunity with a thunderous return drawing the error from Lucic-Baroni.
Kerber gained the double break with the 1999 Wimbledon semifinalist committing an untimely unforced error in a marathon 14-minute game.
In the fourth game, the second seed held serve with ease to lead 4-0 and she dropped her first game of the tournament by drawing a backhand forced error.
This year's Wimbledon finalist had no problems again by serving with ease in the sixth game to extend her lead at 5-1 and forced the Croat to serve to stay in the opening set.
Lucic-Baroni opened the seventh game with her 13th winner but a double fault followed, however, Kerber's backhand unforced error gave the Croat a small chance at 5-2 down to salvage something from this set.
The second seed served out the opening set to love with new balls, clinching it with an ace out wide in 32 minutes with a 6-2 scoreline.
The German stands the second set brightly
The former world number 32 struggled to hold serve once again at the start of the second set, quickly trailing at 0-40, but she saved one of the break points in a nine shot rally with a sweet forehand winner, however, the Croat had the open court to put a backhand volley away but placed it, into the net to give Kerber the break in the opening game of the second set.
Lucic-Baroni wasn't lying down for Kerber and she immediately broke back with a forehand winner in the corner, but the German didn't let that bother her by starting the third game with a backhand winner behind the baseline, constructing another sweet point with the Croat wrongfooted, and Lucic-Baroni's fifth double fault, followed by a tame unforced error in the net, gifted Kerber the break advantage again to lead 2-1.
The Australian Open champion was cruising with another service hold to lead 3-1, and another double fault handed Kerber a commanding 4-1 lead with a double break that seemed to be unassailable.
Lucic-Baroni fights back
Surprisingly, Kerber constructed an error-strewn game by starting the sixth game with a double fault, two back-to-back unforced errors, and forehand unforced error to get broken to love, giving Lucic-Baroni one of the breaks back.
The world number 56 applied more pressure on Kerber by holding serve by virtue of Kerber's failed backhand drop shot going into the net to trail 4-3 but still a break down.
However, Lucic-Baroni was building on her momentum breaking Kerber to 15 with a backhand return winner down the line to get the second set leveled at 4-4.
In the ninth game, Kerber was trying to stop the rot with Lucic-Baroni playing more aggressive tennis causing Kerber to become erratic and produce more unforced errors, however, the German created a break point chance with Lucic-Baroni's unforced error but Kerber failed to capitalise having the Croat wrong-footed and missed a shot in the corner to break.
Lucic-Baroni had Kerber on the stretch once again causing a forehand forced error, and a backhand forced error gave the former top 35 player a lead in the set for the first time at 5-4.
The second seed couldn't believe what was unfolding, and had to serve to stay in the second set with the German becoming tight with a crouched forehand going into the net, and Lucic-Baroni followed this up with a backhand winner to get the game to 15-30.
A backhand unforced error handed Lucic-Baroni a first set point which was quickly snuffed out with Kerber finding a first serve out wide, forcing a backhand unforced error, a couple more unforced errors got Kerber out of jail to level the opening set at 5-5.
In the 11th game, Lucic-Baroni held serve easily sealing the game with an ace and Kerber followed suit by holding to love to take the second set into a tiebreaker.
Kerber saves set points and wins the match
Lucic-Baroni opened the tiebreak on serve, and the opening three points went with serve helped with unforced errors as both players were tight. The Croat produced a crosscourt backhand winner to level the tiebreak on serve at 2-2, and a couple more unforced errors took the game leveled at 3-3 at the change of ends.
However, the Croat took the initiative with a forehand winner on Kerber's serve to have a mini-break advantage at 4-3 but failed to consolidate the mini-break with a backhand unforced error with Kerber getting it back on serve.
Both players found good first serves to get it leveled at 5-5 but a poor second serve from the German's racquet gifted Lucic-Baroni, a second set point chance and a 6-5 lead on her serve but failed to convert it with a backhand error to take the tiebreak at 6-6 at the second change of ends.
Lucic-Baroni produced an unreturnable serve out wide to muster a third set point chance at 7-6 but Kerber responded with her own unreturnable first serve to get it at 7-7, another unforced error sprung from the Croat's racquet which gave Kerber her long-awaited first match point at 8-7.
The Croat served, and unfortunately, a forehand went long to give Kerber a tight victory, 6-2, 7-6 (7) with a big sigh of relief from the German's face.
Match stats
Kerber produced only 11 winners in this contest with Lucic-Baroni having a staggering 37, however, the Croat had an overwhelming 55 unforced errors, and Kerber only had 15.
The Australian Open champion knows that she will need to maintain her concentration to have any chance of winning the US Open, and she will play CiCi Bellis in the third round at Flushing Meadows.