WINSTON-SALEM, N.C. — Defending champion John Isner and top-seeded Jo-Wilfried Tsonga had straight-sets victories Thursday night to set up a semifinal match in the Winston-Salem Open.

WINSTON-SALEM, N.C. — Defending champion John Isner and top-seeded Jo-Wilfried Tsonga had straight-sets victories Thursday night to set up a semifinal match in the Winston-Salem Open.

Second-seeded Tomas Berdych and seventh-seeded Sam Querrey also won their quarterfinal matches at the Wake Forest Tennis Complex in the final hard-court tournament before the U.S. Open.

Isner had 21 aces in beating David Goffin 7-6 (7-5), 6-3, while the sixth-ranked Tsonga needed only 53 minutes to dispatch sixth-seeded Marcel Granollers 6-1, 6-2.

Berdych, ranked seventh in the world, rallied to beat Steve Darcis 4-6, 6-2, 6-0, and Querrey topped fourth-seeded Alexandr Dolgopolov 7-5, 4-6, 7-6 (7-3).

Isner, born in nearby Greensboro, N.C., had 12 aces in the first set against Goffin, who saved four break points in the set to force the tiebreaker. But Isner had four aces in the tiebreaker, and got a key break on the seventh point to get the advantage. Isner then broke Goffin's serve in the fifth game of the second set, and closed out the set and match with another service break.

Tsonga, the highest-ranked player in the field at No. 6, had little trouble dealing with Granollers, breaking his first two serve attempts in the opening set, and adding two more service breaks in the second.

While Berdych's run of games held on serve ended at 29 with a pair of breaks in the first set, he had 10 aces and broke Darcis' serve seven times.

That included a run of six consecutive breaks over the second and third sets, and Berdych won the last nine games to advance to the semifinals for the third time this season.

Querrey had 20 aces against Dolgopolov, who also had his serve broken twice in the first set. But the Ukrainian got a key service break in the second set to even the match, and kept Querrey scrambling in the third set.

However, Querrey got two break points in the tiebreaker to go up 5-1, and closed out the match with an overhead winner for his first win in three tries against Dolgopolov.

New Haven Open

At New Haven, Conn., Caroline Wozniacki remained undefeated in New Haven, but her quest for a fifth consecutive title here may hinge on her right knee.

Wozniacki suffered an injury early in the second set of her 6-2, 6-1 quarterfinal win over Dominika Cibulkova of Slovakia. She was hopeful, but not certain, that she would be able to play in today's semifinal against Maria Kirilenko.

On the other side of the draw, Czech star Petra Kvitova clinched the U.S. Open Series title with her quarterfinal win over Lucie Safarova.

The world's fifth-ranked player had little trouble with her friend and countrywoman, recording 10 aces and no double-faults in a 6-3, 6-3 win.

The series championship, based on points earned in five U.S. hardcourt tournaments this summer, makes Kvitova eligible for a bonus of up to $1 million depending on her finish in next week's U.S. Open.

She will play and Sara Errani of Italy, who beat Marion Bartoli of France 6-4, 6-2 in last quarterfinal. Errani jumped out to a 4-0 lead in the first set and hung on for the straight set win.

Texas Open

At Grapevine, Texas, third-seeded Roberta Vinci advanced to the Texas Open final, routing Bojana Jovanovski 6-0, 6-0.

Vinci will face second-seeded Jelena Jankovic in the final.

Jankovic, from Serbia, beat Casey Dellacqua 7-5, 6-4.

Vinci won three of her six career WTA Tour singles titles last year.