Two-time champion Juan Martin del Potro beat South African Kevin Anderson in straight sets Friday to reach the semifinals at the $1.3 million Citi Open tennis event.

The top-seeded del Potro, who won this event in 2008 and 2009, gained a 7-6 (7-0), 6-3 triumph over the No. 7 seed on the hardcourts at FitzGerald Tennis Center.

With the victory, del Potro moved to 5-0 all-time against Anderson and has a semifinal match Saturday against Germany's Tommy Haas. The third-seeded Haas upended 11th seed Grigor Dimitrov of Bulgaria, 7-6 (7-5), 7-6 (7-3). Haas was last year's runner-up to Alexandr Dolgopolov.

The other semifinal will be between No. 8 seed John Isner and Dmitry Tursunov. Isner, the 2007 runner-up, topped 16th seed and 2010 finalist Marcos Baghdatis, 6-7 (5-7), 6-4, 6-4. The Russian Tursunov defeated Aussie Marinko Matosevic, 6-3, 4-6, 7-6 (7-4).

The 2013 Citi Open champ will collect $292,200.