Novak Djokovic says his triumph over Alexander Zverev at the China Open proves that he can still beat the Tour’s best players.

The 39-year-old recovered from a set down to defeat US Open champion Zverev 4-6, 6-4, 6-4. Battling on court for two-and-a-half hours, Djokovic won 82% of his first service points. He is only the third man to beat a top-three player after their 39th birthday since the ATP Rankings system was introduced in 1973. The others are Ken Rosewall, three times, and Jimmy Connors, once.

“This is probably one of the two best matches that I played this year, next to the one against Sinner in the semis of the Australian Open,” Djokovic told reporters in Beijing.

“I’m very thrilled to win against probably the best player in the world at the moment.

“Sascha has been on a row playing incredible tennis, particularly the last couple of months with his US Open win.

“He’s always been a top player. We knew that it was just a matter of time before he would clinch his first Grand Slam title.”

Zverev has been one of the standout Grand Slam players this season, winning both the French Open and US Open and reaching the Wimbledon final. However, he has won only two out of 11 matches against top 10 players since January. According to OptaAce, he has become only the second top-five player to lose 10 or more matches against top 20 players in back-to-back seasons since 1973.

Despite the German’s lacklustre record against high-ranked opposition, Djokovic is drawing confidence from his latest triumph as he aims to keep playing into his 40s. He is already the oldest man in the current ATP top 100.

“These kinds of matches are the biggest motivation for why I keep on competing and why I keep on pushing myself pretty much on a daily to train and get myself on this level,” he said.

“That’s a kind of proof to me that I can still beat the best players in the world on the biggest stage.

“Things are a bit different nowadays. It’s hard to be consistently playing at the highest level like the youngsters. I’m really happy with myself and proud of the effort.

“The feeling overall is really good. Of course, when you’re playing this well, then confidence is higher, then you forget about all the issues and challenges, and you just keep on moving.”

The challenges he refers to are his physical struggles in recent weeks. Djokovic mentioned during the summer that he suffers from a long-standing health issue but hasn’t disclosed publicly what the exact problem is. It is understood to worsen in humid conditions, with cramping and vomiting occurring.

Djokovic’s next test will be against Daniil Medvedev, who is currently on a seven-match winning streak. Medvedev has yet to drop a set in the tournament, defeating Francisco Cerundolo 7-6(4), 6-3 in the quarter-finals.

“I know his game really well,” Djokovic said of the Russian. “He won a tournament last week. He’s loving the kind of conditions in China. It’s no surprise.

“I’ll have to come up with another great performance if I want to have a chance to win.”

At the China Open on Sunday, Djokovic became the first man in the Open Era to win his first 32 matches at a singles event.