Dominic Thiem beat Stefanos Tsitsipas in the opening singles match of the ATP Finals on Sunday as Rafael Nadal prepared to launch his bid for a first title at the elite eight-man event.
In a repeat of last year’s final at London’s O2 Arena, won by Tsitsipas, US Open champion Thiem stumbled after winning a first-set tie-break but found his range again to win 7-6 (7/5), 4-6, 6-3.
Thiem was impressive on serve in the first set, winning 79 percent of service points, but failed to convert three break points against the Greek world number six.
The Austrian third seed found himself in deep trouble when trailing 4-1 in the tie-break but battled back and made his first set point count when Tsitsipas went long with a backhand lob.
Tsitsipas produced a forehand winner in the third game of the second set to break the Austrian and haul himself back into the contest, facing no break points as he levelled the match.
The defending champion appeared to have the momentum but it was Thiem who drew first blood in the deciding set, earning a break with a delicately dinked forehand at the net in the second game.
The fifth game ultimately proved to be decisive. Tsitsipas had a chance to break but caught the net with a powerful backhand and could not engineer another break point in a game that contained six deuces.
In the evening match in Group London 2020, second seed Nadal, appearing at the end-of-season event for the 10th time, takes on Russian debutant Andrey Rublev.
The 20-time Grand Slam champion has qualified for the ATP Finals for a record 16 consecutive years but has missed six editions due to injury.
Earlier, Novak Djokovic received the ATP Tour No. 1 trophy after finishing the year at the top of the rankings for a record-equalling sixth time.
The Serbian, who has drawn level with American Pete Sampras, said: “Obviously I am super proud of it, but I have mixed emotions because of what is going on in the world. I can’t be ignorant to that, although I have achieved one of the biggest goals in sport.”
Top seed Djokovic, who is competing in Group Tokyo 1970 alongside Daniil Medvedev, Alexander Zverev and Diego Schwartzman, plays his opening match on Monday.
London’s O2 Arena is hosting the ATP Finals for the 12th and final season before the year-end championships moves to Turin next year.