Juan Martin del Potro and John Isner headline a strong field headed to the Citi Open. The Argentine, who is using a protected ranking of seven to earn a main draw entry into the tournament. Del Potro is a three-time champion at Rock Creek Park, winning his last title in 2013 over John Isner.

The American is a regular in Washington DC and all over the North American hard court swing as a matter of fact. As the US number one, Isner tries to make appearances at all the hard court events across North America in the summer, beginning his run in Atlanta and ending in Winston-Salem, depending on how well he does in the two big Masters 1000s events in Canada and Cincinnati.

John Isner of the United States reacts against Kei Nishikori of Japan in the men's singles final during the Citi Open at Rock Creek Park Tennis Center on August 9, 2015 in Washington, DC. (Photo by Patrick Smith/Getty Images)
John Isner of the United States reacts against Kei Nishikori of Japan in the men's singles final during the Citi Open at Rock Creek Park Tennis Center on August 9, 2015 in Washington, DC. (Photo by Patrick Smith/Getty Images)

More Former Finalists in the Field

2014 finalist Vasek Pospisil heads back to DC. That year, him and Milos Raonic contested in the first-ever all-Canadian final in ATP World Tour history. Countryman Milos Raonic edged him out in straight sets, finding no problem taking out Pospisil

Marcos Baghdatis, Gael Monfils, and Viktor Troicki are the three other former finalists in the field. Troicki was the victim in del Potro’s first title in Washington while Baghdatis fell to David Nalbandian in 2008. Monfils was the 2011 finalist, losing to ageless wonder Radek Stepanek.

Talent Pool Deep

Tomas Berdych will likely be the top seed heading into the event, currently ranked eighth on the ATP World Tour. Big-hitters such as Kevin Anderson, Nick Kyrgios, Borna Coric, Ivo Karlovic will all be there as well. Bernard Tomic will also be making an appearance.

Benoit Paire, Ernests Gulbis, Grigor Dimitrov, and Alexandr Dolgopolov are all players who are very capable of doing well. All four players are capable of flashes of brilliance but haven’t had the best 2016s so far. Good runs in DC will be huge for their momentum heading into the Olympics should they decide to play.

American Pool Deep

There will be plenty of American talent on display outside of Isner. Youngsters Taylor Fritz and Reilly Opelka were originally given wild cards, but Fritz has gotten his ranking high enough to earn a direct entry into the event. Brian Baker will be using his protected ranking of 56 to get into the event.

Steve Johnson, Denis Kudla, Sam Querrey, Rajeev Ram, Jack Sock, and Donald Young join the other four previously mentioned Americans, trying to become the first American since Andy Roddick in 2007 to lift the Citi Open title.