KEY BISCAYNE, Fla. " Confronted with an opponent who kept charging, Roger Federer rushed his shots as he searched to find a rhythm.
The fifth game gave him plenty of opportunity. Serving at 2-all, 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 Tuesday night at the Sony Ericsson Open.
The No. 2-seeded Federer's reward: a berth in the quarterfinals Wednesday night against Andy Roddick. Federer has won 16 of their 18 matches but lost to Roddick in the Key Biscayne quarterfinals last year.
In the final match Tuesday, No. 1-ranked Rafael Nadal came from behind in successive sets to beat Stanislas Wawrinka 7-6 (2), 7-6 (4). The grueling match lasted 2 hours, 42 minutes before Nadal closed out the victory with a backhand crosscourt passing shot at 12:20 a.m.
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."
Despite the loss the tournament represented progress for Dent, who's ranked No. 467 and mounting a career comeback after being plagued by back trouble for three years.
"It's really exciting for me," said Dent, a former top-30 player. "The next level for me is going to be foot speed and fitness. I'd love to play Roger again in a few months when I really get a chance to get my legs under me."
The No. 5-seeded Roddick also left the baseline behind as he beat 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, No. 4 Andy Murray, No. 6 Juan Martin del Potro, No. 8 Fernando Verdasco and No. 10 Jo-Wilfried Tsonga.
Djokovic will play Tsonga in the first men's quarterfinal 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."
Said Federer: "It seems like Andy's changed a couple of thing in his game, so should be a good match."
Nadal and Wawrinka had fans roaring into the early morning with a series of scrambling exchanges. Nadal twice sprinted at an angle across the court to save points with seemingly impossible scoop shots at the net.
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 for another 25 minutes.
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 6-3, 6-2, and Verdasco defeated No. 18 Radek Stepanek 6-2, 6-2.
No. 8-seeded Svetlana Kuznetsova outlasted 18-year-old Caroline Wozniacki in the first women's quarterfinal, 6-4, 6-7 (5), 6-1. When the 2-hour, 54-minute match in humid, 80-degree sunshine 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, who beat unseeded Samantha Stosur 6-1, 6-0.