Tomas Berdych was "really happy" to record his first win at the ATP World Tour Finals this afternoon.
The world number seven was taken the distance by Janko Tipsarevic, with Berdych finally emerging victorious in a tie-break.
It was Berdych's second match against a Serbian player at the tournament, having lost to world number one Novak Djokovic on Monday.
"They have been two incredible matches," Berdych told Sky Sports News. "The Serbians have made me work hard.
"I'm really happy that I could finish it today."
The 26-year-old will now take on Spain's David Ferrer in his final group fixture, with the winner likely to advance through to the semi-finals.
