(Updates with Wednesday's results)
Serbia's Novak Djokovic and Czech Tomas Berdych picked up wins Wednesday in Group A action at the ATP World Tour Finals.
In the afternoon match at London's O2 Arena, Djokovic, the world's top-ranked player, rallied to defeat world No. 3 Andy Murray 4-6, 6-3, 7-5 for his second straight victory at this year-end championship event.
Djokovic started slowly with a lot of uncharacteristic unforced errors, but he grabbed a critical break of serve in the sixth game of the second set and went on to force a decider.
The Serb then won a tight third set to take the match in two hours and 34 minutes.
"(It was) another great match, another great performance from both of us," said Djokovic, who lost a five-set thriller to Murray in this year's U.S. Open final.
"I hope that people who watched it agree with my opinion? I didn't expect anything less other than a tough match that went down the wire and was decided on the last point."
In the night match, Berdych needed one hour and 52 minutes to score a 7-5, 3-6, 6-1 victory over Jo-Wilfried Tsonga and avenge his loss to the Frenchman in the semifinals of last year's ATP World Tour Finals.
After a closely fought first two sets, Berdych completely dominated the latter stage of the match, winning 21 of the last 25 points for the victory.
Tsonga, who has lost his first two matches in London, needs a win Friday against Murray and a victory by Djokovic over Berdych to have any chance of reaching the semifinals.
Djokovic can book a spot in the semifinals by defeating Berdych, while the Czech would be guaranteed of a berth if he wins Friday and Murray loses.
In Group B action Thursday, world No. 2 Roger Federer of Switzerland will take on Spain's David Ferrer, while Serbia's Janko Tipsarevic will square off against Argentina's Juan Martin del Potro.
Federer trounced Tipsarevic and Ferrer edged Del Potro on Tuesday. EFE