WORLD No2 Novak Djokovic admitted he passed a gruelling physical test in beating 17-time grand slam champion Roger Federer at the O2 Arena last night, just two days after winning the Paris Masters.
Djokovic, who beat Federer in the semi-final in Paris last week, had the better of the Swiss star in three sets once again, triumphing 6-4, 6-7, 6-2 in two hours 23 minutes in their opening Group B match at the ATP World Tour Finals.
And the Serbian former world No1 said: “It’s necessary to be on top of your game and perform to your best if you want to try and beat Roger Federer.
“He has a tremendous record in London, both in the Tour Finals and at Wimbledon.
“It was a big challenge physically to be able to play this well, so soon after Paris and to win against Roger Federer is incredible.
“It’s a big win, the good thing now is there is a day off and then I’ll get ready for my next match against [Juan Martin] Del Potro.”