Rafael Nadal came from behind in both sets to beat Stanislas Wawrinka of Switzerland 7-6 (2), 7-6 (4) on Tuesday and reach the quarterfinals in pursuit of his first Sony Ericsson Open title.
The top-ranked Nadal won despite converting only one of 12 break-point chances. He had four match points at 5-4 in the second set, but the No 16-seeded Wawrinka hit a succession of big serves to stay alive.
The two grueling sets lasted 2 hours, 42 minutes before Nadal closed out the victory with a backhand crosscourt passing shot at 12:20 a.m. local time. His opponent in the quarterfinals on Thursday will be sixth-seeded Juan Martin del Potro of Argentina.
Second-seeded Roger Federer overcame eight break points in a remarkable sequence to take the lead for good and he beat American Taylor Dent 6-3, 6-2 .
Federer will meet American Andy Roddick in the quarterfinals Wednesday. Dent's only break-point chances against Federer came in their 26-point fifth game. Federer double-faulted twice in the game and dumped several hurried shots into the net, which had him mumbling, then screaming. "I had to save so many break points over and over again," Federer said.
"I was serving against the wind, so I was struggling with my first serve there a bit. He did well to keep coming at me and creating opportunities. It was definitely a big game for me." Federer finally whacked a service winner to hold, and his game steadied after that.
Dent played serve-and-volley and also charged the net behind some returns, but he won barely half his points at the net. "I like playing against that kind of style," Federer said.
"When I came on tour, this is how many guys were playing, even myself _ coming to the net, forcing the issue, keeping the points short." Fifth-seeded Roddick also left the baseline behind as he beat Frenchman Gael Monfils 7-6 (2), 6-4.
Roddick won 22 points at the net, showing a willingness to move forward that's part of his more well-rounded game under his new coach, Larry Stefanki. While Roddick has improved his volley and backhand in recent months, he still possesses an overpowering serve and won 38 of 44 first-serve points against the No. 9-seeded Monfils.
Roddick leads the ATP Tour in victories this year with a record of 26-4. "I feel good and I feel confident," he said.
"I think the big difference is you get to those 30-all points, and I just feel calm and like I'm going to play my point the way I want to. I have maybe some more options now."
Other men's fourth-round winners were No. 3 Novak Djokovic of Serbia, fourth-seeded Andy Murray of Britain, del Potro, Spanish No. 8 Fernando Verdasco and No. 10 Jo-Wilfried Tsonga of France. Djokovic will play Tsonga in the first men's quarterfinal on Wednesday.
On Thursday, Nadal will face del Potro, and Murray will play Verdasco. Roddick's most recent match against Federer came in the Australian Open semifinals in January. Federer won in straight sets. "The thing that Roger seems to do really well against me is serve really well," Roddick said. "Obviously it'll be tough. But I'm going to go out there and just go after it."
In other men's fourth-round matches, Djokovic beat No. 21 Tomas Berdych 6-3, 6-2. Murray routed Viktor Troicki 6-1, 6-0. Tsonga won 6-7 (4), 6-3, 6-2 against No. 7 Gilles Simon, the highest-seeded man to be eliminated.
Del Potro beat No. 11 David Ferrer of Spain 6-3, 6-2, and Verdasco defeated No. 18 Czech Radek Stepanek 6-2, 6-2. Eight-seeded Svetlana Kuznetsova of Russia outlasted 18-year-old Dane Caroline Wozniacki in the first women's quarterfinal, 6-4, 6-7 (5), 6-1.
When the 2-hour, 54-minute match in humid conditions ended, Kuznetsova slowly crumpled to the court in exhaustion and relief. The 2006 champion will play in the semifinals Thursday against No. 11 Victoria Azarenka of Belarus, who beat unseeded Australian Samantha Stosur 6-1, 6-0.