ATP World Tour Finals: Novak Djokovic takes title after Roger Federer pulls out injured

Novak Djokovic won his third consecutive ATP World Tour Finals title on a walkover after Roger Federer pulled out ahead of the match.

The world No 2 fought for almost three hours to defeat countryman Stan Wawrinka in the semi-finals on Saturday night, saving four match points, and did not leave the O2 Arena until the early hours of Sunday morning.

There was speculation Federer may again have been feeling his back and that only increased when he failed to show up for a scheduled practice session on Sunday afternoon.

The announcement was made following the doubles final, which was won by Bob and Mike Bryan, with Federer taking to the court to explain the situation to the fans.

He said: "Unfortunately I'm not match fit to play match tonight. Clearly I wish it wasn't this way. You try all year to be ready for the ATP World Tour Finals and I didn't want to end this way.

"I tried everything I could last night and today - painkillers, rest - until the very end, but I can't compete at this level with Novak. In a final like this and at my age, it would be too risky. I hope you understand."

The news was a huge disappointment for the sell-out crowd, with the clash between the world's top two a highly-anticipated occasion, but they accepted it with little dissent.

And the mood picked up when they were told the match would be replaced by an exhibition clash between Djokovic and Andy Murray, which the world No 1 won 8-5.

Federer's withdrawal meant Djokovic became the first player since Ivan Lendl in the 1980s to win three consecutive World Tour Finals titles, with the Serbian unbeaten at the O2 since 2011. ...SkySports