Roger Federer broke Novak Djokovic's service to take early lead in both the sets they played on Monday, but the World No. 1 bounced back elegantly on both the occasions to register a memorable victory over the greatest tennis player and World No. 2 by 7-6 (6), 7-5 to clinch the ATP World Tour Finals title.

''It's not the first time that Roger starts against me so well,'' The Associated Press quoted Djokovic as saying. ''I've experienced before his aggressivity, really trying to put his mark on the match. It's what he's done again.''

The two-time defending champion Federer won 12 points of the first 14 and took 3-0 lead in the first set. In the fourth game, he won first point again. It seemed likely that the Swiss maestro would win the first set easily, but it did not happen.

"I tried to convince myself that I will turn it around and fight. It happened again. I managed to deliver my best when I needed it most." Djokovic said.

Djokovic hit back hard and took the set at 5-4. Federer was firm to win the first set and forced the tiebreaker.

''Maybe a bit of regret because I had the lead twice first before him,'' said Federer. ''At the end of the day, that doesn't matter. You have to get over the finish line in the set and then obviously at the match. He was better at that today.''

Federer is one of the most popular tennis players in London. But the crowd cheered loudly for best shots of both the players throughout the match.

''It's best way to finish the match, I guess, with a passing shot, one of my favorite shots,'' Djokovic said. ''He came in. That was the only space left for me to make a passing shot, and I made it.''

Djokovic won the first set with forehand shot.

In the second set, Federer's mistakes helped Djokovic win the title. He won the match with a backhand shot.

It was a good year for Federer, who won 71 matches and reached 10 finals in 2012. On the other hand, for Djokovic it was a great year, as he closed the season with wins in 75 matches and won three Grand Slam titles.

''I shouldn't have been broken as often as I was broken today,'' said Federer. ''But then again, that obviously has something to do with Novak, as well.''

Federer had 42 unforced errors in the final, while Djokovic had only 28.

''Obviously I was going to try to go after my shots and not just hand it to him. That's just how I play tennis,'' Federer said. ''If I have 80 errors and I win the match, I don't care. I really don't.''