TOKYO, Oct 4: Argentina’s Juan Martin Del Potro on Friday denied David Ferrer a chance to defend his Japan Open title, beating the top seed in straight sets in the quarter-finals.

The 20-year-old Del Potro — ranked 12th in the world after a blistering summer that saw him win four titles — powered his way into the semi-finals with a 6-1, 7-5 victory over the Spanish world No 5.

In the semi-finals, Del Potro will play last year’s runner-up, Richard Gasquet of France, who easily dismissed 2003 champion Rainer Schuettler of Germany, 6-3, 6-2.

Second seed Andy Roddick, fresh off a victory at the China Open last weekend, will face ninth seed Tomas Berdych of the Czech Republic in the other semi-final.

Roddick, a former US Open champion, breezed past Viktor Troicki of Serbia, 6-3, 6-4, while Berdych pulled off a 6-0, 6-4 upset win over third seed Fernando Gonzalez of Chile.

Del Potro attributed his success since Wimbledon to changes in his game and mindset.

“I’ve improved a lot. I won two tournaments on hard courts and reached the quarter-finals at the US Open. I did many things to change my game. That’s the reason, I think,” said Del Potro.

Del Potro never faced a single break point in the first set, but got himself in trouble in the third game of the second set. He double-faulted twice to go down 15-40, but rebounded with two strong first serves to stave off the break.

After breaking Ferrer to go ahead 5-3, he failed to serve out for the match by netting a forehand, but finally finished the match in the 12th game with a forehand winner down the line.

In the women’s draw, top seed Caroline Wozniacki of Denmark easily beat Thai ace Tamarine Tanasugarn 6-4, 6-1 to set up a semi-final against Jarmila Gajdosova of Slovakia, the winner over Klara Zakopalova of the Czech Republic 7-5, 7-5.

Fifth seed Kaia Kanepi of Estonia edged past Anastasia Pavlyuchenkova of Russia 7-6 (7-4), 7-6 (7-1), while eighth seed Aleksandra Wozniak of Canada defeated Australia’s Samantha Stosur 7-5, 6-3 to set up the other semi-final.

Friday’s results (prefix number denotes seeding):

Men’s singles:

Quarter-finals: 9-Tomas Berdych (Czech Republic) bt 3-Fernando Gonzalez (Chile) 6-0, 6-4; 2-Andy Roddick (US) bt Viktor Troicki (Serbia) 6-3, 6-4; 4-Richard Gasquet (France) bt 12-Rainer Schuettler (Germany) 6-3, 6-2; 5-Juan Martin Del Potro (Argentina) bt 1-David Ferrer (Spain) 6-1, 7-5.

Women’s singles:

Quarter-finals: 8-Aleksandra Wozniak (Canada) bt Samantha Stosur (Australia) 7-5, 6-3; 5-Kaia Kanepi (Estonia) bt Anastasia Pavlyuchenkova (Russia) 7-6 (7-4), 7-6 (7-1); Jarmila Gajdosova (Slovakia) bt Klara Zakopalova (Czech Republic) 7-5, 7-5; 1-Caroline Wozniacki (Denmark) bt 7-Tamarine Tanasugarn (Thailand) 6-4, 6-1.

TURSUNOV CRUISES AHEAD

METZ (France): Dmitry Tursunov moved into the semi-finals of the Metz Open on Friday by beating Carlos Moya of Spain 6-3, 6-3.

Tursunov had nine aces and converted three of his 10 break points.

The fifth-seeded Russian next faces seventh-seeded Radek Stepanek of the Czech Republic in the semi-finals. Stepanek defeated Eduardo Schwank of Argentina 3-6, 7-6 (7-4), 6-4. Fourth-seeded Paul-Henri Mathieu also advanced, hitting 12 aces to beat Janko Tipsarevic of Serbia 7-6 (7-4), 6-3.

Mathieu will next face Andrian Mannarino, a 20-year-old Frenchman who defeated Marc Gicquel 6-4, 7-6 (7-3) in only his second ATP tournament.

Results:

Quarter-finals: 4-Paul-Henri Mathieu (France) bt Janko Tipsarevic (Serbia) 7-6 (7-4), 6-3; 5-Dmitry Tursunov (Russia) bt Carlos Moya (Spain) 6-3, 6-3; Adrian Mannarino (France) bt Marc Gicquel (France) 6-4, 7-6 (7-3); 7-Radek Stepanek (Czech Republic) bt Eduardo Schwank (Argentina) 3-6, 7-6 (7-4), 6-4.

SAFINA OUSTED

STUTTGART: Venus Williams overwhelmed third-seeded Russian Dinara Safina 6-4, 6-2 to reach the semi-finals of the Stuttgart Grand Prix on Friday.

The sixth-seeded American was

too strong and consistent for Safina,

making just eight unforced errors in a high-quality match that took just one hour 16 minutes.

Williams will go on to face second seed Jelena Jankovic of Serbia, who won a two-hour struggle with seventh seed Vera Zvonareva of Russia 7-6, 7-6.

Jankovic, who will take over as world number one next week, took the first-set tie-break 10-8 only to drop her serve at the start of the second. She finally broke back in game eight and forced another tie-break with a similar outcome.

In the other half of the draw, Olympic champion Elena Dementieva fell to Victoria Azarenka of Belarus 7-6, 3-6, 6-1.

The unseeded Azarenka hit with real venom and was helped by a stream of errors from fourth seed Dementieva as she sealed victory in two hours 54 minutes on centre court.

Azarenka will play her semi-final against another Russian after Nadia Petrova brushed aside China’s Li Na 6-2, 6-3, finishing off with a booming ace down the middle at the indoor event.

Petrova, the 2006 champion, should have a big advantage in terms of physical condition after Azarenka’s exhausting match took everything out of her.

After two tight sets Azarenka ran away with the third, building a 5-0 lead before Dementieva belatedly reacted.

The Russian saved three match points on serve before holding and threatened to get one break back in the next only for three unforced errors to seal her fate.

Results:

Quarter-finals: 2-Jelena Jankovic (Serbia) bt 7-Vera Zvonareva (Russia) 7-6 (10-8), 7-6 (7-5); 6-Venus Williams (US) bt 3-Dinara Safina (Russia) 6-4, 6-2; Nadia Petrova (Russia) bt Li Na (China) 6-2, 6-3; Victoria Azarenka (Belarus) bt 4-Elena Dementieva (Russia) 7-6 (8-6), 3-6, 6-1.—Agencies