Roger Federer: It was a "rough" start

Roger Federer has conceded that he made a "rough" start to his group encounter against Tomas Berdych at the ATP World Tour Finals yesterday evening.

The former world number one lost seven of the first eight points to hand Berdych a 2-0 lead, but Federer rallied to eventually win through 6-4 6-2.

Speaking to reporters after his victory, Federer admitted that it took him some time to adjust to the speed of the court at London's O2 Arena.

"Clearly it was not the best start. It was a bad start. One of the worst starts I've had in years. No first serves, two double faults, nothing coming from the baseline. It was rough," said the Swiss player.

"Thankfully I was able to pick it up. The surface does play slow here. If you get to see too many second serves, clearly you can crawl back into the match. You can get your chances from the baseline to find rhythm quickly.

"As the match went on, I definitely started to play better, started to serve better. I think what I underestimated a little bit in some ways was that it was a first round. I think I was playing very well in practice."

The win has extended Federer's overall record against Berdych to 15-6.