WASHINGTON: Argentina’s top-seeded Juan Martin Del Potro booked a semifinal 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.

Women’s top seed Angelique Kerber of Germany was ousted by defending champion Magdalena Rybarikova 7-6 (7/0), 3-6, 6-3.

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

Tursunov, ranked 61st, seeks his first semi-final since February at Marseille. That was his first appearance in the last four since winning in 2011 at s-Hertogenbosch.

Slovakian seventh seed Rybarikova advanced to a Saturday semifinal against Russian third seed Ekaterina Makarova, who barely had won her opening game when Romania’s Monica Niculescu retired with a left wrist injury.

The other women’s semifinal will match French fourth seed Alize Cornet — who ousted Romanian fifth seed Sorana Cirstea 7-6 (7/5), 6-2 — against Germany’s Andrea Petkovic, who eliminated Argentina’s Paula Ormaechea 4-6, 6-1, 6-3.

Granollers downs Monaco in Kitzbuehel final

In Kitzbuehel, Austria, Spain’s eighth seed Marcel Granollers won the Kitzbuehel Cup clay-court event on Saturday after coming from a set down to beat Juan Monaco 0-6, 7-6 (7/3), 6-4 in the final.

Monaco, seeded two, appeared on course to win his second title of the year when he comprehensively won the opening set to love in just 23 minutes.

However, the 53rd-ranked Granollers, who knocked out defending champion Robin Haase in the semi-finals, came back to level the match in a second set tie-break before eventually holding his nerve to win the decider.

Granollers was 4-0 and then 5-2 up, but finally converted his fourth match point on Monaco’s serve to take the third set 6-4.

It is the Spaniard’s fourth career tour title, but his first since 2011.