SHANGHAI, China (AP) -- It was one of those stretches that most players can only dream about. For Roger Federer, it was another day at the office -- thanks to a lot of hard work off the court.
Against Rafael Nadal, the man who has been his main rival for three years and who held an 8-5 edge in their past meetings, the top-ranked Federer won 15 straight points in 11 minutes. The Spaniard, who had been matching him stroke for stroke for eight games, was left to wonder what hit him.
Suddenly the rivalry was a rout, and Federer was in the Masters Cup final with a 6-4, 6-1 victory. Seeking his second consecutive title and fourth overall at the season-ending event for the world's top eight players, the Swiss star will play Sunday against sixth-ranked David Ferrer, who beat No. 5 Andy Roddick 6-1, 6-3.
"I was really pleased with my performance for the last 1 1/2 sets," Federer said. "Before that it was tough. Rafa had a bit of the upper hand. But after that, I got in the zone and played incredibly.
"Once I get on a roll, it's hard to stop me. When it happens again for me, it's not as big of a surprise because this is why I work my tail off, basically. It seems it's paying off again."
When Federer dropped his opening match here, it was his second loss in a row for the first time in 4 1/2 years. There was rumbling that maybe he was slipping a little, maybe the rest of the field was starting to reel him in.
Federer heard the rumors, but didn't take them seriously.
"I knew the reasons why I lost in Paris," he said. "I knew the reasons why I lost my first-round match. I'm very honest in my losses, why I lose. I think in the long run, that is a good thing. I turned it around."
He really kicked into high gear while serving at 4-4 in the first set. Nadal, who earlier squandered his only break point, pulled ahead 15-30. Federer then ran off 20 of the next 21 points, including 15 in a row. Looking stunned, the Spaniard managed to win only three points in the first five games of the second set.
Nadal said his rival was playing "very crazy."
"When he's 100 percent, he's playing in another league. It's impossible to stop him," Nadal said. "I fight. I fight. I fight. Nothing to say. Just congratulate him."
He finally held at love to break Federer's streak of seven games. Serving at 5-1, Federer hit an overhead winner to set up match point, and Nadal netted a backhand to finish it off in 59 minutes -- 13 minutes less than Federer needed to blitz Roddick on Friday.
Federer landed 83 percent of his first serves. He ended up with 26 winners to 16 unforced errors and yielded only 11 points in his nine service games.
"The way I played today, I wish I could play every time like this against him," Federer said. "But it's not that easy."
Now the question is whether Ferrer can continue his hot streak. He has dropped only one set in four matches and was fresh, confident and sharp from the start, while Roddick seemed to be showing the effects of the short 20-hour turnaround from his loss to Federer the night before. Ferrer last played Thursday.
"Today, I played very good," Ferrer said. "Now I want to enjoy this moment."
After Roddick held serve to start the match, Ferrer ran off six games in a row, with Roddick never managing a game point. Roddick's serve lost some of its usual zing, and he got a massage on his lower back after getting broken for the second time to trail 4-1. He won only 11 of his 26 service points in the first set.
"It was really stiff. My range of motion was really bad," Roddick said of his back. "Normally you're able to work your way into a match a little bit. With David, he comes out, makes balls right away. After I got some stuff on it, it loosened up pretty well for the second set."
Nimble and quick at the baseline, Ferrer's defense was nearly flawless. He ripped winners from both sides on the run, and punished Roddick when he came in, sending groundstrokes past him or at his feet.
Ferrer broke Roddick for the fourth time to pull ahead 4-2 in the second set, aided by a pair of seemingly impossible crosscourt winners that left the American staring at him in disbelief.
"In the second set, I was hitting the ball well, four, five, six times to corners, and to no avail," Roddick said. "That's about as well as I've hit a ball and lost in a set in a while."
Roddick, who was coming back from an injury layoff and looked sharp in winning his first two matches, now will prepare for the Davis Cup final against Russia at the end of the month.