Roger Federer shook off a slow start to top Andy Murray 7-6 (7-5), 6-2 and advance to the championship match at the Barclays ATP World Tour Finals, where world No. 1 Novak Djokovic awaits.

Federer, the world No. 2 and winner of this event a record six times, fell behind early by dropping serve in the opening game of Sunday night's match at London's O2 Arena.

But the Swiss great broke back in the eighth game and then won the first-set tiebreaker when Murray netted a backhand.

Federer shifted into another gear in the second set, outclassing the Scotsman and clinching victory in one hour and 33 minutes with a forehand winner down-the-line.

"I started the match off very well," Murray said in the post-match press conference.

"I was going for my shots a lot. I was playing very aggressive on the return. Then he started to serve a little bit better. I missed a few more returns. Then, when he got the break back, he started to play better. I hung on a little bit the end of the first set."

With the victory, Federer advanced to the final of this year-end event for the eighth time in 10 years and will square off against Djokovic on Monday night.

"It's exciting, no doubt about it. I love playing against Novak," the Swiss said. "He's had a great year. He's had a great tournament so far ... It is a big opportunity playing sort of the last match of the season, and facing off against Novak."

The Serb, who won this title in 2008, rallied to defeat Argentina's Juan Martin del Potro in Sunday's first semifinal 4-6, 6-3, 6-2. He also was undefeated in his round-robin group.

Federer dropped one match in his group, a three-set loss to Del Potro.

No matter what happens in the final, Djokovic is assured of finishing as the world's top player for the second consecutive season.

The eight-man Barclays ATP World Tour Finals is the biggest tournament on the men's tennis calendar after the four Grand Slams.