World number one Novak Djokovic has launched into the semi-finals of the ATP World Tour Finals after a tough 6-2 7-6(6) contest with Tomas Berdych.
The Serbian headed into the match knowing that a first-set win would clinch a place in the final four and he wrapped it up swiftly by grabbing the first break of serve and maintaining his dominance on the court.
Djokovic's trademark athleticism came into play as Berdych tried to blast some strong returns in the O2 Arena but Djokovic was relatively unharmed and claimed another break to push on, take the set and grab a place in the semi-finals.
The second set was Berdych's chance to turn things around and the Czech didn't disappoint by winning a break instantly after losing his serve to Djokovic in the previous game.
Berdych continued to hold well and the set was forced to the wire, with Djokovic determined to finish off the game in the tie-break and prevent a third and final set.
The Czech professional claimed the first two points and looked composed around the court but Djokovic found answers to Berdych's shots and closed off the match by winning the tie-break and knocking his opponent out of the competition.
