Djokovic, who has had a terrific season winning three Grand Slam titles and claiming the world No.1 ranking in the process, won the hard fought battle 3-6, 6-3, 7-6 (7-3) here Monday, reports Xinhua.

The Serb found Berdych at his best in the first set. The Czech World No.7 needed just one break, and it came in the second game, to take the first set. Djokovic found his touching the second set and Berdych’s game fell apart with a string of unforced errors. Djokovic made it a set-all taking the second set  6-3, but was in danger of losing when dropped his first service game and then faced a match point double-faulting.

The Serb recovered to take the 12th game before cruising through the tiebreak. Briton Murray suffered a bitter defeat at the hands of world No.5 Spaniard David Ferrer 6-4, 7-5 in his Group A opening match.  

"I had a problem with my groin," revealed Murray, who took a medical timeout after the first set. I didn't move particularly great, but I still had opportunities." Murray broke first in both sets, but succumbed to a more consistent Ferrer, whom he defeated in the previous three meetings this year.

"He's just very, very solid. He gives you very few points," said Murray. "He returned well today, didn't make hardly any mistakes on the return, so he was always putting pressure on my service game. And that's the main difference."

Although Murray still has at least two matches to play in the round robin, the 24-year-old said he will decide later whether or not to play the remaining matches. "I can decide until one minute before the match Wednesday if I want to," Murray added. "So I'll see how I feel tonight and tomorrow and decide."