Novak Djokovic turned on the style to outclass old adversary Rafael Nadal and reach the final of the ATP World Tour Finals with a 6-3, 6-3 victory at the 02 Arena on Saturday.

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

Djokovic has now drawn level with Nadal in head-to-head matches in what is the most prolific rivalry since tennis turned professional, with both players having 23 victories.

World number one Djokovic, bidding for a fourth consecutive title at the season-ender, and a fifth in total, launched an early onslaught, breaking Nadal's serve in the second game of the match with four sweetly-struck, clean winners.

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

"Novak for the moment is almost unbeatable," Nadal told reporters. "He was better than me and he deserved to do what he did during the whole season.

"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 year but for a French Open final defeat by Stanislas Wawrinka, suffered a first indoor defeat in three-and-a-half years against Roger Federer this week.

He responded by beating Tomas Berdych to secure a semifinal berth in London 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.

He will face either Federer or Wawrinka in Sunday's final.