Novak Djokovic is trying to win the ATP World Tour Finals for the first time since 2015, and he got off to a strong start Monday.
After Rafael Nadal and Dominic Thiem played well in their opening matches Sunday, Djokovic headlined the draw in Day 2 of the year-end tournament from London in a group also containing Daniil Medvedev, Alexander Zverev and Diego Schwartzman.
Even in a round-robin format, the pressure is on, as only two from each group advance to the semifinals.
Here is the latest from Monday's action at the the O2 Arena.
No. 1 Novak Djokovic def. No. 8 Diego Schwartzman 6-3, 6-2
No. 4 Daniil Medvedev def. No. 5 Alexander Zverev 6-3, 6-4
Full draw and standings available at the event's official site.
Djokovic has already clinched the year-end No. 1 trophy for the sixth time and has won the ATP Finals five times, including four straight from 2012 to 2015, but he is always looking to add to his resume.
He put himself on the right path Monday with a straight-sets win over Schwartzman, who was making his debut at this event.
The first set featured some struggles from Djokovic, who was down a break early and made a few unforced errors. He still did enough to take it 6-3:
There were also some impressive winners along the way:
Djokovic was in complete control in the second set, facing zero break opportunities while winning both break points against Schwartzman.
He was especially impressive attacking his opponents' second serve, winning 13 of 20 points after the Argentinian missed his first serve.
It was enough for Djokovic to grab an opening win, although every game is counted in the round-robin format.
Monday provided little in the way of surprises as Medvedev dispatched Zverev in straight sets.
The Russian was rolling so much that he was able to break out an underhand serve in the second set and still get the better of his opponent on the point.
The two opened the match by exchanging service breaks in the first two games. From there, however, Medvedev took firm control. He broke Zverev's serve again to move ahead 4-2 and held in the next game to take a commanding 5-2 advantage.
The second frame was more competitive as neither player budged through six games. Zverev dropped serve in the seventh game to fall behind, and that was the opening Medvedev needed to seal the victory.
Zverev struggled on serve throughout the match. Allowing an opponent to have nine break-point opportunities is a recipe for disaster, and the 23-year-old German lost 15 of his 19 second-service points while committing seven double faults.
No. 2 Rafael Nadal vs. No. 3 Dominic Thiem
No. 6 Stefanos Tsitsipas vs. No. 7 Andrey Rublev