World tennis number one Roger Federer has extended his mastery of Andy Roddick, winning 6-4, 6-2 at the Masters Cup in Shanghai in a match played largely for pride.
Both players had already earned semifinal berths from their group after fourth-ranked Nikolay Davydenko beat seventh seed Fernando Gonzalez 6-4, 6-3 earlier on Friday.
All that was at stake was determining whom Federer and Roddick would face next in the end-of-year tournament for the top eight men in the world rankings.
The Swiss star, who improved his career record against fifth seed Roddick to 15-1, will play second-ranked Rafael Nadal on Saturday, while Roddick meets sixth seed David Ferrer, who went undefeated in his group.
Federer won the Masters Cup in 2003, 2004 and 2006 and was runner-up in 2005, when he was beaten by David Nalbandian in a five-set thriller.
Friday's match was nearly a repeat of the Australian Open semifinals when Federer annihilated Roddick, allowing the American only six games in three sets.
Because he already had clinched his semifinal place by winning his first two matches, Roddick had said he had no pressure on him this time and hoped he could cut into Federer's advantage.
But Federer, who had looked in danger after losing his opening match against Gonzalez, was thoroughly dominant. He never faced a break point and blunted Roddick's powerful first serve and picked on his second one. The Swiss star finished with 33 winners to only 13 unforced errors.
Federer said even he was impressed by his performance, which included hitting 83 per cent of his first serves.
"I know that my game matches up well with his, but that doesn't mean I'm going to beat him all the time," Federer said. "Andy has been trying many, many different things out against me. It's dangerous for me to play against him, especially with the guy having such a big serve. Today I read it well."
Clearly frustrated, Roddick smashed a ball into the stands after losing the first set, then broke his racket by smashing it against his left foot five times when Federer broke him for a 3-0 lead in the second set.
Serving at 5-2, Federer held at love, squirting a clean forehand winner to finish it in 61 minutes.
Federer wasn't ready to say he's sorry for his domination, clearly recalling his one loss to Roddick, four years ago in Canada.
"I lost it 7-6 in the third, and that was my first opportunity to become No. 1 in the world," Federer said. "He didn't feel sorry for me back then either."
Some sceptics were speculating that Federer might be starting to slip after he lost his first round-robin match to give him a two-match losing streak for the first time in four-and-a-half years. Roddick certainly wasn't among the doubters.
"It seems like most times we play, he's on top of his game, which is a little annoying," Roddick said.
"I guess I just have to figure out what about my game brings out the best in him and try to adjust. You see some of the guys who beat him are quick. Unfortunately, that's not my strength. You kind of have to go with what you're good at, try to make adjustments."
Davydenko had already been eliminated from the semifinals by dropping his first two matches. While inconsistent again, the Russian knocked out Gonzalez, who had hoped to emerge from his group if he won and Federer lost.
Davydenko essentially won a battle of attrition against Gonzalez, who was at the top of his game in beating Federer on Monday and then showed his well-known inconsistency by losing his last two matches.
Davydenko was hit or miss throughout the match, with 33 winners offset by 35 unforced errors. Uncharacteristically, he frequently charged the net, where he either hit a deft volley or looked like a deer caught in the headlights with bad mistakes.
But Gonzalez was even more uneven, and even his stinging forehand let him down. He smacked a clean winner around the net post for one of only seven forehand winners to 17 unforced errors.
swissinfo with agencies
Roger Federer has led the world rankings of the ATP (Association of Tennis Professionals) since February 2004.
In 2007 he won seven titles, including three Grand Slams - Australia, United States and Wimbledon.
The ATP named Federer "Player of the Year" for the third year in a row.
He was Swiss sportsman of the year in 2003, 2004 and 2006.
Federer has been an ambassador for the children's aid organisation Unicef since April 2006.
Date of birth: August 8, 1981
Plays: Right-handed, single-handed backhand
Turned professional: 1998
Titles: 52 (Grand Slams: 12)
Prize money: $36,007,078