A year late maybe, but the ATP World Tour Finals will get a fitting climax to the season on Sunday after world number one Novak Djokovic and Swiss maestro Roger Federer marched to consummate semi-final victories.

Djokovic turned on the style to outclass old adversary Rafael Nadal 6-3 6-3 while in Saturday's evening session at a packed O2 Arena six-times champion Federer beat fellow Swiss Stanislas Wawrinka 7-5 6-3 with a masterly display.

They will meet for the 44th time on Sunday when 34-year-old Federer will hope to make up for the disappointment of 12 months ago when, after also beating Wawrinka in the semis, he was unable to face Djokovic because of a back injury.

Federer, who had an unblemished record in group play including ending Djokovic's late-season 23-match winning run, hit back from 4-2 down in the opening set to brush aside his compatriot in little more than an hour.

"Novak should be knocked out by now! No, I am joking," world number three Federer, who last won the year-ender in 2001 when he beat Jo-Wilfried Tsonga, said on court.

"He played a great match against Rafael Nadal earlier today and I'm sure it will be a fantastic meeting."

Spaniard Nadal had looked more like his old dominant self with round-robin wins against Andy Murray, Wawrinka and David Ferrer, but the world number five was no match for Djokovic who was at his clinical best.

"Novak for the moment is almost unbeatable," Nadal said.

Djokovic has now drawn level with Nadal for the first time in what is the most prolific rivalry since tennis turned professional. Both players have 23 victories.

"Obviously, after 46 matches and 10 years of professional tennis, I managed to tie my head-to-head score with Nadal," Djokovic told reporters. "It took a lot of time.

"I think I was a few levels under him at the beginning of my career. Nadal was alongside Federer dominating the tour. I just couldn't really do much against him."

"I won the last, what, three times we played against each other (before Saturday). That all plays a major role in the mental approach to these match-ups."

Djokovic, bidding for a fourth straight title at the season-ender, and a fifth in total, made his intentions clear from the start as the ball whistled off his strings.

The 28-year-old broke Nadal's serve in the second game of the match with four exquisite winners that the Spaniard, one of the sport's best athletes, could only watch whiz by.

From then on the Serb was barely troubled by the 14-times grand slam champion who could make little impression and did not sniff a single break point in the 79-minute encounter.

"PLAYED FANTASTIC"

"He was better than me and he deserved to do what he did during the whole season," a magnanimous Nadal said.

"He played just fantastic. When somebody's doing like this, just the only thing I can do is congratulate him and just wish not the best of luck for the next year!"

Djokovic, who would have claimed a rare calendar-year grand slam this season but for a French Open final defeat by Wawrinka, suffered a first indoor defeat in 3-1/2 years against Federer this week, going down in straight sets.

He then beat Czech Tomas Berdych to secure a semi-final berth and was back at full throttle against Nadal, crunching 24 winners and dropping just three points on his first serve.

Some trademark defence, followed by a dipping backhand that forced a Nadal volley error, gave the Serbian two break points in the fifth game of the second set and he converted after Nadal succumbed in a fierce baseline rally.

There was no way back from there for Nadal.

Djokovic was clearly in a hurry to finish the job, breaking again at 5-3 with another flurry of winners.