Federer was broken for the first time in three matches but handled his debut meeting with Sergiy Stakhovsky of Ukraine 6-3, 6-4, while two-time defending champion Novak Djokovic beat Florian Mayer of Germany 7-5, 6-4.

Federer awaited the winner of the all-French quarterfinal between Gilles Simon and Richard Gasquet. Djokovic will play Tomas Berdych in a rematch of their Australian Open quarterfinal. Djokovic won that, then beat Federer in the semis and Andy Murray in the final.

“Yeah, tough one. (Berdych is) playing really well in the last year and a half,” Djokovic said. “He's a quite consistent player right now. He has a very powerful serve, very fast baseline strokes, very flat, so I guess I need to be patient and wait for my chances.” Stakhovsky saved three match points but Federer finally won when Stakhovsky hit a return wide.

“I thought it was a tough match, tougher than the last couple,” Federer said.

Djokovic trailed Mayer 5-3 in the first set but the unseeded German's serve abandoned him and Djokovic wasn't troubled again.

“The ball was going faster today, and he took it to me from the start,” Djokovic said. “Already first game he was on the net, twice, three times. I was not moving my legs well. I was making lots of unforced errors.” Djokovic finished better than he started, however, winning the last four games in the first set and the last five in the second.

Next up was Berdych, who beat Phillip Petzschner of Germany 7-5, 6-4 in just under two hours.

The third-seeded Czech broke Petzschner three times in the first set but dropped serve twice. Berdych wasted six set points, closing it out when Petzschner hit a forehand long.

The second set was just as close, with Berdych making the decisive break for 5-4.

Berdych conceded he had trouble with the big-serving Petzschner, whom he lost to last year.

“Philipp likes to play big serves, sometimes come to the net, a lot of slice in the backhand side and then he just makes a winner like that,” Berdych said. “He does not give you a rhythm on court at all.”

In Doha, Qatar, Caroline Wozniacki won 12 straight games to beat Flavia Pennetta of Italy 6-2, 6-0 on Thursday, setting up a semifinal against Marion Bartoli at the Qatar Ladies Open.

The No. 1-ranked Dane, who won the Dubai title last week, extended her winning streak to eight matches after losing the first two games of the match.

Wozniacki wore a Liverpool football shirt with Steven Gerrard's name on the back during the warmup on Thursday.

"I'm a big fan of Liverpool," Wozniacki said. "Since Liverpool is playing tonight (against Sparta Prague), I thought it would be nice and even the fans liked it." Wozniacki made just seven unforced errors against Pennetta, who appeared to lose heart after dropping serve in a 12-minute fourth game. The top-seeded Wozniacki finally won it with one of her trademark backhand returns to draw level at 2-2.

"I was playing really good tennis," Wozniacki said. "I stayed calm and had to go for my shots." Pennetta, who has never won against Wozniacki in their four previous meetings, could fair no better in the second set, committing 21 unforced errors.

Bartoli ended Peng Shuai's challenge in just 71 minutes with a 6-2, 6-2 victory. Peng lost her serve in the first game and could not recover from the initial blow.

"I thought I played well," Bartoli said. "I could have finished earlier. I mean, it could have been 6-1 in the second instead of 6-2, even 6-0, but overall it was a great performance."

In Delray Beach, Floriday, American qualifier Ryan Sweeting upset US third seed Sam Querrey 7-6 (7/5), 6-4 on Wednesday to reach the quarterfinals of the $442,500 ATP Delray Beach International Championships.

Sweeting won six of the last seven points, denying Querrey's fightback bid in the final game. Sweeting fell behind 0-40 but saved three break points, then rescued another with a second-serve ace before winning on his only match point.

"I feel like I'm playing good tennis," Sweeting said. "I'm one of the Americans consistently moving up, maybe not at a fast rate, but it's going in the right direction." Sweeting, ranked 118th, advanced to a Friday date against Japan's 66th-ranked Kei Nishikori who breezed past American wild card James Blake 6-3, 6-4.

Nishikori's only ATP crown came at Delray Beach in 2008.

French eighth seed Adrian Mannarino advanced to the second round by rallying to defeat Argentina's Leonardo Mayer 1-6, 7-6 (7/3), 6-4.

Mannarino will next face Colombian qualifier Alejandro Falla and could meet US second seed Mardy Fish in the quarterfinals. Fish is the highest-ranked player in the field after US top seed Andy Roddick withdrew due to illness.

In the night match, sixth seeded Janko Tipsarevic outlasted Blaz Kavcic 6-2, 6-7 (8/10), 6-3.