Top-seeded Juan Martin del Potro booked a semifinal matchup against Tommy Haas with a straight-set victory over Kevin Anderson at the Washington Open on Friday. Seventh-ranked del Potro, the 2009 U.S. Open winner and the Washington champion in 2008 and 2009, beat the South African seventh seed 7-6(0), 6-3 while third seed Haas defeated Bulgarian 11th seed Grigor Dimitrov 7-6(5), 7-6(3).

del Potro, who never faced a break point in the match, rolled through the first-set tie-breaker, winning it at love when Anderson netted a backhand. That was part of his run of 15 points in a row, including the first six of the second set on his way to the first break of the match for a 2-0 lead.

del Potro held serve to the finish, which came after one hour and 45 minutes on a service winner.

Isner fired 18 aces to defeat Cyprus’ Marcos Baghdatis 6-7(5), 6-4, 6-4 while Tursunov outlasted Australia’s Marinko Matosevic 6-3, 4-6, 7-6(4).

Meanwhile, Rohan Bopanna and Andre Begemann suffered a quarterfinal exit after losing 6-4, 7-6(1) to Conrad Treat Huey and Dominic Inglot.

On the women’s side, top seed Angelique Kerber was ousted by defending champion Magdalena Rybarikova, who won 7-6(0), 3-6, 6-3.

The results:

Quarterfinals: Men: Dmitry Tursunov bt Marinko Matosevic 6-3, 4-6, 7-6(4); John Isner bt Marcos Baghdatis 6-7(5), 6-4, 6-4; Tommy Haas bt Grigor Dimitrov 7-6(5), 7-6(3); Juan Martin del Potro bt Kevin Anderson 7-6(0), 6-3.

Doubles: Conrad Treat Huey & Dominic Inglot bt Rohan Bopanna & Andre Begemann 6-4, 7-6(1).

Women: Andrea Petkovic bt Paula Ormaechea 4-6, 6-1, 6-3; Alize Cornet bt Sorana Cirstea 7-6(5), 6-2; Ekaterina Makarova bt Monica Niculescu 1-0 (retd.); Magdalena Rybarikova bt Angelique Kerber 7-6(0), 3-6, 6-3.

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