Stanislas Wawrinka defeated Tomas Berdych 6-3 6-7 (0-7) 6-3 to clinch victory in the opening singles match of the ATP World Tour Finals
The Swiss player did not drop serve throughout the contest and lost just three points on his serve in the deciding set as he completed the win in two hours and 25 minutes at the O2.
Berdych dominated the second-set tie-break but was elsewhere blighted by eight double faults and could not convert any of the five break-point opportunities he was given.
Wawrinka, who was playing in his first match at a year-end tournament, takes an early lead in Group A while Berdych faces an uphill task with Spaniards Rafael Nadal and David Ferrer still to come.
Wawrinka beat Berdych in the fourth round of the US Open recently and it was the world No 8, backed by a vocal Swiss support, who made the better start this time.
With Berdych struggling with his serve and looking sluggish around the court, Wawrinka made the breakthrough in the sixth game and was rock solid until he came to serve out the set.
At that moment the seventh seed's nerve wobbled, but he eventually wrapped it up on his fifth set point.
Berdych improved at the start of the second set and Wawrinka did well to force a tie-break, fighting back from 0-40 in the eighth game.
The breaker was dominated by the Czech, however, as Wawrinka failed to win a single point.
Wawrinka then called for the trainer to have his thigh massaged in the decider, but by then he was back ahead and showing little sign of any potential injury out on court.
A break in the fourth game proved enough, with Wawrinka clinching victory on his first match point when Berdych hooked a forehand wide
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