ATP World Tour Finals 2019 Results: Federer, Thiem Highlight Tuesday Winners

Dominic Thiem pulled off a thrilling comeback triumph over Novak Djokovic in the group stage of the ATP Tour Finals at the O2 Arena in London on Tuesday.

Thiem fell behind after a tight first set but was able to battle back brilliantly against the Serbian. In the decider, the fifth seed appeared to let his chance of a win slip, as he failed to serve out the match at 6-5 and then fell 4-1 behind in the tiebreak. However, he dug deep to continue his stunning start and reach his first semi-finals in the competition.

Earlier on, Roger Federer got his competition up and running with a win over Matteo Berrettini. The Swiss, who is seeded third in London, was beaten in his opener by Thiem on Sunday but recovered with a 7-6 (2), 6-3 win.

Here are the results and highlights from the third day of the season-ending competition, as well as the schedule for Wednesday's play.        

Tuesday Results

(3) Roger Federer bt. (8) Matteo Berrettini: 7-6 (2), 6-3

(5) Dominic Thiem bt. (2) Novak Djokovic: 6-7 (5), 6-3, 7-6 (5)

Wednesday Schedule

(1) Rafael Nadal vs. (4) Daniil Medvedev

(6) Stefanos Tsitsipas vs. (7) Alexander Zverev

Tuesday Recap

After Federer suffered a surprise loss to Thiem, the pressure was on to respond against Berrettini.

Early in the match, both players struggled to get a read on the other man's serve. The only break point came at the end of the set, when Federer was able to up the ante. His opponent dug in and forced a tiebreak.

Federer was able to move through the gears and took it 7-2. Berrettini's shoulders did slump a little after that setback, and the 20-time Grand Slam champion was able to race to victory in the second set.

Tennis TV shared some of the best moments from Federer's high-class performance:

Afterward, the man himself said it's strange to lose a match and then play at the same venue a couple of days later.

"It's unusual to lose and come back again," the veteran stated, per Kevin Mitchell of the Guardian. "I did it last year. There's no reason to be too down on yourself. You come here to play three matches. I had a day off, and there are ways to get rid of that loss. I did it hanging out with my kids."

Djokovic and Thiem played out a what will likely be remembered as the match of the tournament to this point.

Both men broke the other once in the first set before they settled in to a tiebreak. Again, there was little between the players, but when Djokovic got his first set point, he was able to take it, with Thiem planting a forehand into the net.

The Live Tennis account summed up a thrilling set:

However, Thiem didn't lie down and was able to catch his opponent napping at the start of the next set, breaking to move 2-0 ahead and then consolidating. The Austrian was nerveless in seeing it out, setting up a decider.

The ATP Media Info account noted both men have fine records in third-set shootouts:

Here is the moment Thiem leveled up the contest:

Thiem initially appeared as though he would seize the initiative in the third, as he broke in the first game. However, Djokovic clung on and was able to restore parity at 3-3 before moving 4-3 in front.

The Austrian stayed in touch, and after a brilliant game to break at 5-5, he had the chance to serve for the match in the next game. Nerves clearly got to him, though, as Djokovic showed his champion credentials to force a tiebreak.

In a high-pressure breaker, Djokovic went 4-1 ahead, only to see Thiem string together five consecutive points and give himself two match points. The Austrian took the second of them to earn one of the most dramatic triumphs of his career.