Nadal tops Tsitsipas, but still needs help to advance at ATP Finals

With only one semifinal spot in the ATP Finals up for grabs, Rafael Nadal knew what was at stake in his final round-robin match: win, or go home. His opponent, Stefanos Tsitsipas, had already punched his ticket into the weekend, but was playing for the first seed in the group, and a match against Roger Federer.

Faced with that burden—and, eventually, a one-set deficit—the recently crowned year-end No. 1 rallied to take care of his business on Friday, defeating the 21-year-old Greek, 6-7 (4), 6-4, 7-5, in two hours and 52 minutes.

Nadal's future at this event now resides with Daniil Medvedev, who at 0-2 has been eliminated from title contention, but will play a big part in determining the title contenders. If the Russian beats Alexander Zverev later today, Nadal will advance. If he doesn't, Zverev will move on.

“I did all the things that I could today. I fought until the end, two days ago [and] today,” Nadal said to the crowd in his on-court interview. “If I am able to play in front of you tomorrow against Roger, it will be a huge honor. And if not, I really hope to see you next year. So many thanks. Thank you very much everyone.”

In their first indoor meeting, both Nadal and Tsitsipas did a great job protecting their service games in the first set before it required a tiebreaker. Having exchanged early mini-breaks, Tsitsipas made a big move to earn two set points, closing it out with an ace after 58 minutes.

In the fifth game of the second set, Nadal squandered two break points, allowing Tsitsipas to remain unbroken the entire week. The Spaniard got another break-point opportunity in the seventh game, but again was not able to convert. Finally, he converted one in his next return game to go up 5-4. A game later, he took the set to mount his comeback.

At 2-2 in the third set, Tsitsipas dug himself out of a hole to erase two break points, and saved another one in his next service game. But a break in the 11th game gave Nadal a 6-5 advantage, and the 19-time Grand Slam chanmpion consolidated with a hold for the win.

Today’s loss means that Tsitsipas will play Roger Federer for a spot in the tournament final. In his first two round-robin matches, Tsitsipas took out Daniil Medvedev and Alexander Zverev, despite playing win an injured foot.

"[Zverev] has, in a way, inspired me to step it up and be part of the Top 10. So in a way I actually owe him a lot," said Tsitsipas. "Also playing Rafa, Roger, Novak [Djokovic], Andy [Murray]—I haven't played Andy, but I think there is plenty to learn from them. You know, you have been watching them on TV. You have always wanted to be part of that.

"When you see something that you have been dreaming of, I think there is always a spark, kind of an extra reason to play."

Nadal has never won the ATP Finals. If he goes on to capture his first this year, it will be on the strength of his resolve against Tsitsipas and thanks to Medvedev, who at the moment is now Rafa's favorite tennis player.