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.

"I was pressing a little bit in that first set," said Isner, 2-1 against Tsonga, including a Davis Cup victory last April. "I was waiting for him to lose the set or make a mistake on a big point rather than me going after the ball. But I was happy with the way I played in the tiebreaker, and I played much better in the second set."

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.

"I played well," Tsonga said. "I was into the match from the beginning and played good tennis. I don't know if he played his best tennis, I think he was a bit injured. But I played good tennis."

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.

"He was playing really smart, so I needed to change something," Berdych said. "I stepped a little bit closer to the baseline, and started to hit the ball a little faster. It changed the whole rhythm."

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.

"It seemed that things just changed dramatically in the tiebreaker," said Querrey, the winner in Los Angeles last month. "It feels good to get the win today, but the matches are going to get tougher. I just going to have to play better if I want to keep winning."