Roger Federer still playing a brand of tennis few can match at ATP Finals

Federer defeats Djokovic in straight sets (1:15)

Roger Federer defeats Novak Djokovic for the first time since 2015 to advance to the semifinals of the ATP Finals. (1:15)

LONDON -- For Roger Federer, it seems revenge is a dish best served up in front of a cauldron of fans yelling his name.

Four months after failing to convert either of his two match points in the final set of their Wimbledon final, the 38-year-old's 6-4, 6-3 victory over Novak Djokovic in London on Thursday sent the Swiss into the semifinals of the ATP Finals and ended the Serb's chances of finishing the year as the world No. 1 for a record-equaling sixth time.

That honor goes to Rafael Nadal, who moves alongside Federer and Djokovic in holding the year-end No. 1 spot five times. At 33, the Spaniard is the oldest man ever to finish the year on top of the rankings, and he owes a bottle of champagne or two to the oldest man out there.

And it means a lot. Having nailed a return at the feet of Djokovic to clinch victory, Federer leaped in the air, yelling in delight. If it will not quite have exorcised all of the demons from Wimbledon, it will surely make Federer walk a little taller.

"It was a great atmosphere, a great opponent ... definitely incredibly special," Federer said. "Just a night I enjoyed from the beginning. I played incredible, and I knew I had to because that's what Novak does and I was able to produce. So it was definitely magical. Tonight was one of those nights where I was clear in the game plan. I got what I kind of expected, and it was a great feeling at the very end. The reaction showed."

The ability to forget losses has always been a special trait of great champions, even if it's scarcely believable. Federer claimed losing at Wimbledon had not affected him as badly as people may have thought.

"I didn't know I hadn't beaten him in a few years, actually," he said. "Didn't feel that way because it was so close in Paris and in Wimbledon against him. I realized I hadn't beaten him since my knee operation [in 2016]. I heard that today.

"I'm just happy at the level I could play today, and obviously it's always special beating Novak, even more so [because] of what happened, but I didn't feel like I had to get rid of the ghosts or anything like that. I feel like I moved on pretty quickly after that. I have been playing very well this season, and I think this victory proves that today."

Federer is into semifinals of the ATP Finals for the 16th time in 17 appearances, an astounding statistic in a sea of incredible statistics. He will play either Nadal or Stefanos Tsitsipas in the semis on Saturday. He is two wins away from a record seventh ATP Finals win, his first since 2011. At 38, he still seems to play a brand of tennis that few can match.

Djokovic, who was livid at his own performance, still found time to express how impressive it is to see Federer do what he's doing.

"It motivates me," he said. "I mean, it shows me it's possible. I have utmost admiration for him and everything he's doing on the court. What he has achieved over the years, and what he's still showing on the court, is phenomenal. He's a role model even for me, as one of his rivals, and one of the toughest opponents I had in my career. Looking at his career and what still he is doing, it inspires you."

At Wimbledon, when Federer served for victory at 8-7 in the final set, he was undone by a slightly misplaced serve and an under-hit approach. At London's O2 on Thursday, in front of a crowd at least 90% behind him, he served beautifully, dropping just three points on serve in the first set and breaking twice in the second set as Djokovic's resistance failed.

Djokovic was inconvenienced by some pain in his right elbow early in the second set, but he said it had not affected him in the rest of the match. But whether it was the demands of his brutal three-set loss to Austria's Dominic Thiem on Tuesday or the effects of another long season, for once it seemed as if the engine was running low.

"There was not much that I did right in this match, to be honest," Djokovic said. "He did everything right. I was just playing too neutral. I couldn't read his serve well. Just a pretty bad match from my side.

"I'm not happy with the way I finished the season. Obviously, this is not the way I want to play on the court, first of all. You've got to accept that you have these kind of days and move on. If I have to draw the line, I think it was still a very good season, winning two slams and five titles."

Djokovic said he hopes to be fit to lead Serbia in the revamped Davis Cup finals, which begin in Madrid on Monday.

"I hope it's nothing that will really [make me] unable to play in Madrid," he said. "The pain was pretty sharp. But I could play the rest of the match, so if I had something really serious, I think I wouldn't be able to hold the racket. It was probably just an awkward, quick movement that I did, it did not pose any form of issues later on."

"Of course, the gas tank is not as full as beginning of the season, but I am motivated to join the guys and play there because I have not played Davis Cup for some time."