Federer waltzes into final

Roger Federer will face Novak Djokovic in the World Tour Final after defeating Swiss compatriot Stan Wawrinka 7-5, 6-3 on Saturday.

Earlier, Serbian world number one Djokovic beat Spain's resurgent Rafael Nadal 6-3, 6-3 in his semifinal to secure his place in Sunday's title match.

Third seed Federer beat Djokovic in straight sets in the group stage.

"A great match, I really enjoyed it," Federer said after his win on the hard court of London's O2 Arena.

"It will be a perfect ending only if I win. Novak should be knocked out by now! No, I am joking. He played a great match against Rafa earlier today and I'm sure it will be a fantastic meeting."

The clash was a repeat of last year's semifinal, which ended in bad blood between the Switzerland team-mates.

In the 2014 semis, they embarked on one of the most draining matches of the season -- nearly three hours of cut-throat tennis that Federer won 4-6, 7-5, 7-6 (8/6).

On top of that, there was a bust-up -- Wawrinka taking umbrage at what he saw as inappropriate words from Federer's wife Mirka from the players' box at a key point in the third set.

But the pair appeared to patch up their differences, teaming up to win a first Davis Cup for Switzerland.

Federer went into the Wawrinka match with a 17-3 lead in career clashes between the two, including all their matches on a hard court.

He won two of their three matches this year, including their last encounter in the US Open semi-finals, where Federer went on to lose to Djokovic.

At the coin toss, the umpire, like a boxing referee, asked both players for "a clean fight" and "no blows below the belt".

Wawrinka saw off a match point to hold for 5-3, but Federer was cruising by this point and ended the contest with a straightforward service game. The pair shook hands warmly at the net.

Djokovic said clashes against Federer were always nervy affairs as he prepared to face his rival for a second time this week -- Federer having got the better of the Serb in the group stage.

But Djokovic had a near-perfect performance as he beat Rafael Nadal 6-3, 6-3 in their semifinal clash on Saturday.

"I don't feel unbeatable, but it definitely feels great when I'm playing the way I played," Djokovic said after his dazzling display against Nadal.

"I've lost against Roger three times this year. When he's on, it's hard to play him," said the Serb, who has beaten Federer four times in 2015, all in finals.

"We always play matches with a lot of tension. There is a lot at stake. I know I have to be on top to win against him."

Djokovic could claim $1,050,000 in prize money if he wins, while Federer would receive $2,228,000 for winning the title undefeated.