World No. 2 Novak Djokovic recovered from losing a tense first set to defeat Dominic Thiem 6-7, 6-0, 6-2 on Sunday at the Barclays ATP World Tour Finals in London.
Djokovic survived three set points in the 76-minute first set before Thiem ripped a forehand winner. An angry Djokovic reacted to dropping the set by hitting a ball toward coaches Boris Becker and Marian Vajda in the crowd.
His outburst fired Djokovic up as he broke Thiem in the first game and continued to blank the Austrian in 22 minutes. Thiem won just 10 points in the set.
"Even though I lost the first set, I thought I didn't do too many things wrong," Djokovic said. "It was just the very high quality of his game that prevailed in the first set. I started swinging more freely in the second set. He started making more errors."
Thiem held serve to start the third and deciding set but was broken in his second service game, giving Djokovic an opportunity he did not squander.
"I lost a little bit of energy, not much, but just a little bit (after the first set)," Thiem said. "Of course, against a player like Novak, he immediately steps up. That's how the second set went."
Djokovic has finished four of the past five seasons at the No. 1-ranked player. With a win in London, he could still make it five out of six years. Djokovic has won each of the past four editions of this tournament.
In another match, Canadian Milos Raonic rolled to a 6-3, 6-4 victory over Gale Monfils of France.
Raonic will face Djokovic on Tuesday at the season-ending event. Monfils and Thiem square off the same day.