Dominic Thiem reached his second successive title match at the ATP Finals on Saturday after claiming a tense 7-5, 6-7, 7-6 win over top seed Novak Djokovic. In a clash that saw few chances for either player to make inroads on their opponent's serve, Thiem pounced on the only break point of the opening set to claim a 6-5 lead before comfortably serving out to take the lead. The Austrian third seed had two chances to take control of the match with break points in the fifth and ninth games of the second set only for Djokovic to hold his nerve. It was then Djokovic's turn to apply the pressure when he carved out two set points with Thiem serving at 5-6, but the top seed was unable to convert. The second set was settled in a nerve-wracking tie-break. Even in the absence of fans at London's O2 Arena, the tension was palpable as both players – so solid on serve for the match – began to exchange mini-breaks. Four match points came and went for Thiem – the second squandered on a double fault, the fourth with a majestic forehand winner that caught the line from Djokovic. Eventually it was 17-time Grand Slam champion Djokovic who made the breakthrough when Thiem put a fairly routine groundstroke into the net. Normal service resumed in the deciding set with both players impenetrable on serve: in the first seven games of the set, only five points were dropped by the server. It was perhaps both fitting and inevitable that a match that was so close would be decided on a tie-break. In a curious case of history repeating itself, Djokovic raced into a 4-1 lead only for Thiem to come storming back and clinch the tie-break, and the match, 7-5 – the exact same scenario as when these two met at the ATP Finals last year. Thiem, with his powerful serve and booming groundtstrokes, finished the match with 47 winners compared to Djokovic's 19, although his attacking tendencies saw him produce 35 unforced errors to the world No 1's 25. Thiem also saved all three break points he faced. The victory, delivered after two hours and 54 minutes of gruelling tennis, was the 300th of Thiem's career and was achieved in a year when the Austrian achieved the ultimate breakthrough by <a href="https://www.thenationalnews.com/sport/tennis/dominic-thiem-wins-elusive-first-grand-slam-at-us-open-in-pictures-1.1077281">winning his first Grand Slam title</a> at the US Open. Thiem has now <a href="https://www.thenationalnews.com/sport/tennis/atp-finals-super-focused-dominic-thiem-overpowers-rafael-nadal-1.1113295">beaten Rafael Nadal</a> and Djokovic at the same tournament, further underlying his credentials as one of the very best players in the world. "For sure it was a mental battle. I was so tight in the second-set tie-break," Thiem, 27, said in his post-match on-court interview. "To play these legends is always something special. Playing for the finals here at the ATP Final is also something very special. "I thought after my first big title in New York I would be more calm but that was a mistake. I was just as tight and nervous as before it was so much on the edge this match." Thiem, who is competing at the ATP Finals for a fifth time, reached last year's final but came up short against Stefanos Tsitsipas in a closely-fought encounter. In the 12 months since that match, tennis has endured a disrupted and limited schedule because of the coronavirus pandemic as the sport went into lockdown from March until the end of August. For Thiem, this season has still produced some special memories and he is aiming to finish the year on a high. "I am looking forward to it a lot," he said. "It is the last match of a special but tough year for everyone. We will try and put on a great show for everybody."