McEnroe blames Federer's locker-room row with Wawrinka for quitting Tour Finals

American tennis legend John McEnroe has claimed that 17-time Grand Slam champion Roger Federer had a locker-room row with compatriot Stanislas Wawrinka the night before the Swiss pulled out of the final of the ATP World Tour Finals.

World number one Novak Djokovic was handed his third consecutive title after the Swiss pulled out with a back injury. And Britain number one Andy Murray stepped in at late notice to play the Serb in an exhibition match.

Federer claimed that he hurt his back during his epic semifinal win over compatriot Wawrinka on Saturday. And McEnroe said that afterwards something went on in the locker-room, adding that there was a long talk between the players that extended well into the night, The Mirror reported.

And, the American added that the stress of that, he couldn't confirm all of this, but a lot of this went on and he doesn't think that helped the situation.

Federer and Wawrinka would be teammates when Switzerland takes on France in the Davis Cup Final, starting this Friday.

Federer apologised to the O2 Arena crowd saying that it would be too risky to do this at my age, adding that he hopes they understood.

Murray, who thought his season was over when Federer thrashed him here, lost 8-5 to Djokovic. The Scot, thrashed 6-0, 6-1 by Federer on Thursday, said that he was playing Mario Kart on his sofa when he got the call, adding that he was winning at that.