Swiss world No. 2 Roger Federer smashed British favourite Andy Murray in straight sets, winning his second match at the ATP World Tour Finals on Tuesday.

Both Federer and Murray won their opening matches in straight sets on Sunday, showing they were in form in the season finale. However, when Federer kept his sharpness on Tuesday, the world No. 5 Murray seemed stuck in a sudden downturn.

Although Murray led their head-to-head series 8-5 including two straight-sets wins in two finals this year, Federer only needed one hour and 16 minutes to defeat the Scot 6-4, 6-2.

"I'm surprised that I was able to win my service games that comfortably," said the 16 Grand Slam title holder Federer. "I heard I dropped eight points on my serve. That's not the norm against Andy, who is one of the best return players."

The result means that Federer might qualify for the semifinals before his last round-robin match as long as Spaniard David Ferrer defeats Robin Soderling Tuesday night or Soderling of Sweden defeats Ferrer but in three sets.

"If I got to qualify or not after these two matches doesn't really change my mindset a whole lot," said Federer, who is going to play Soderling on Thursday.

"I think on a level, I saved energy so far. It's been good. Plus I've had the days off in between, like in a Grand Slam. Plus I only have to play two sets, it's nice at the end of the season. I sort of enjoy it.

"I'm excited to play Soderling. I have a great record against him. I hope I can play the same level like I did the last two."

The 29-year-old Federer only lost once in his previous 15 clashes with Soderling.

Murray 23, will play Ferrerplay in his last match in the Group B and he expected that would be a touch match on Thursday.

"I have to serve well against him and get some free points. That will be the main thing I'm looking to improve from today's match," said Murray.

While talking about his performance on Tuesday, Murray said, "I got off to a bad start in both sets, which doesn't help. I returned poorly, served poorly. Against him, that's not going to win you the match."