Argentina's top-seeded Juan Martin Del Potro booked a semi-final matchup against Germany's Tommy Haas with a straight-set victory Friday over Kevin Anderson at the ATP and WTA Washington Open.
Seventh-ranked Del Potro, the 2009 US Open winner and the Washington champion in 2008 and 2009, beat the South African seventh seed 7-6 (7/0), 6-3 while third seed Haas ousted Bulgarian 11th seed Grigor Dimitrov 7-6 (7/5), 7-6 (7/3).
"It's a good opportunity to reach another final but I have to beat a very good player," Del Potro said. "He's playing good this season and he has got a lot of experience. I'll try to play like today or even better."
US eighth seed John Isner, who won his seventh career title last week in Atlanta, will face Russia's Dmitry Tursunov in the other men's semi-final at the $1.76 million hardcourt event, a tuneup for the US Open.
Del Potro, in his first event since losing an epic Wimbledon semi-final to top-ranked Novak Djokovic, has won all four prior ATP matches against Haas without losing a set, including a 2008 Washington semi-final and most recently in the round of 16 this year at Indian Wells.
"Del Potro is one opponent I despise playing in many ways," Haas said. "He has given me a lot of trouble. And he has been playing terrific tennis.
"It's going to be a challenge. I hope I can mix it up, play aggressive and not give him too many points."
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 a run of 15 points in a row by the South American, including the first six of the second set on his way to the first break of the match for a 2-0 lead.
