WASHINGTON: Top seed Juan Martin Del Potro, playing twice in one day for the first time in his career, reached the quarterfinals of the Washington Open with two straight-set triumphs Thursday.

The 2009 US Open winner, a two-time Washington champion, dispatched American Ryan Harrison 6-1, 7-5 in 70 minutes, then returned five hours later to eliminate Australian 14th seed Bernard Tomic 6-3, 6-3 in 69 minutes and advance at the combined ATP and WTA event.

“I feel good,” Del Potro said. “I was training hard before I came here. During the night you feel much better. In the first match the sun was harder for me. In the night I move much better.”

Despite double duty on his first match day since losing the longest semi-final in Wimbledon history to Novak Djokovic after four hours and 43 minutes, the 24-year-old Argentine advanced to a last-eight meeting with South Africa’s 21st-ranked Kevin Anderson, who ousted American Mardy Fish 7-6 (7/2), 6-1.

“For the first day of the hardcourt season, I had a very good day,” Del Potro said. “I beat two young players with good potential. I should play better all the matches.”

Anderson, ranked 21st, broke Aussie James Duckworth in the only extra game he needed to win their rain-halted second-round match 6-3, 3-6, 6-4, and said he doubted world number seven Del Potro’s double would have any impact.

Del Potro has won all four prior matches with Anderson, the most recent last year at Basel.

Del Potro fired six aces and 16 winners to beat Tomic, who committed 26 unforced errors, the last by netting a backhand on match point.

Del Potro and Japanese second seed Kei Nishikori both had their second-round matches postponed Wednesday by rain with two other matches suspended by showers, but Nishikori — ranked a career-best 11th — could not pull off twin wins at the $1.76 million event.

After opening with a 7-5, 6-2 triumph over US wildcard Jack Sock, Nishikori was thrashed by 16th-seeded Cypriot Marcos Baghdatis 6-1, 6-2 in only 58 minutes.

Baghdatis booked a quarter-final berth against US eighth seed John Isner, who won last week in Atlanta and kept alive his hopes for back-to-back titles with a 7-5, 7-5 victory over Somdev Devvarman in their first meeting since Isner lost to the Indian in the 2007 US college final.

Australian Marinko Matosevic withstood a 19-ace barrage to defeat Canada’s Milos Raonic 7-5, 7-6 (9/7) and book a matchup with Russian Dimitry Tursunov, only the Aussie’s fourth career ATP quarter-final.

German third seed Tommy Haas won the last set of a rain-halted match to beat US qualifier Tim Smyczek 3-6, 7-5, 6-3, then beat Croatian 13th seed Ivan Dodig 6-4, 4-6, 7-5 for a quarter-final berth against Bulgarian Gigor Dimitrov.

On the women’s side, Russia’s Olga Puchkova struck a ball in anger and wound up defaulting away the match with Argentina’s Paula Ormaechea after the ball struck a line judge in the knee, sending him to the court writhing in pain.



Te Radwanska sisters reach Carlsbad quarterfinals

In Carlsbad, California, second-seeded Agnieszka Radwanska set up a quarterfinal clash with former US Open champion Samantha Stosur at the WTA Southern California Open Thursday with a straight-sets win over Daniela Hantuchova.

Poland’s Radwanska, the 2010 runner-up and 2011 champion on the hardcourts of Carlsbad, defeated Hantuchova 6-3, 6-3, her sixth victory over the Slovakian in eight career meetings.

She was joined in the quarterfinals of the $795,707 US Open tuneup event by younger sister Urszula, a 6-2, 4-6, 6-3 winner over sixth-seeded Serbian Jelena Jankovic.

Urszula Radwanska’s victory was just one of the upsets of the day, with French wild card Virginie Razzano ousting eighth-seeded Carla Suarez Navarro of Spain 6-1, 6-4.

Razzano next faces third-seeded Czech Petra Kvitova, a former Wimbledon champion.

From 2-2 in the third set, Radwanska won four of the next five games from former world number one Jankovic as she booked her fourth WTA quarter-final appearance of the season.

Another former world No. 1 from Serbia, Ana Ivanovic, made it safely through to the quarters, defeating US qualifier Coco Vandeweghe 7-6 (7/5), 6-3.