LONDON 鈥 Seven-times champion Novak Djokovic shrugged off a slow start to power past unseeded Australian Alexei Popyrin 4-6 6-3 6-4 7-6(3) and into the Wimbledon fourth round on Saturday.

The Serb鈥檚 bid for a record-extending 25th Grand Slam title looked under threat when Mr. Popyrin took a 4-3 lead with a blistering crosscourt forehand winner and sealed the opening set with a second-serve ace.

鈥淚t was another tough match. I didn鈥檛 expect anything less than what we experienced on the court today from Alexei,鈥 said Mr. Djokovic, who was also taken to four sets by Mr. Popyrin at this year鈥檚 Australian Open.

鈥淚 know he was going to come to the match with confidence, a lot of self-belief. He was close to winning (when we played) in Australia earlier this year.

鈥淲ith that serve and powerful forehand, he鈥檚 dangerous on any surface.鈥

Mr. Djokovic was quickly back to his best and normal service was resumed.

Appearing rejuvenated after the roof was closed, Mr. Djokovic went 4-1 up in the second set, when fans erupted on Centre Court as news trickled through that England had beaten Switzerland to make the Euro 2024 semifinals.

The amused second seed simulated a penalty kick that Mr. Popyrin pretended to save, to the delight of fans.

Mr. Djokovic had little trouble in the second and third sets, but faced more resistance in the fourth as Mr. Popyrin dug deep in search of his first win in the pair鈥檚 third meeting, saving three break points to hold in the 11th game.

After ensuring a tiebreak, however, Mr. Djokovic switched on the after-burners to close out the win, finishing with a fiery serve that Mr. Popyrin could only send into the net. 鈥淚 played a good second and third set and the fourth was anybody鈥檚 game,鈥 Mr. Djokovic added.

鈥淗e was serving very well. It was very difficult to read his serve. It was just a very challenging match, mentally as well to hang in there.

鈥淚鈥檓 not allowed to have too big concentration lapses. I think I鈥檝e done well in that regard in one of the best tiebreaks I鈥檝e played this year, that鈥檚 for sure.鈥

Mr. Djokovic arrived at Wimbledon weeks after having surgery on his right knee, having injured it at the French Open, but said he was getting better with every match.

鈥淢y feeling of movement, confidence particularly extreme balls, reaching, sliding. I definitely got better today than in my second match,鈥 he said, referring to his meeting with Briton Jacob Fearnley where he also dropped a set.

鈥淗opefully the direction or trajectory will keep going in a positive way. Let鈥檚 see what happens in the next one.鈥

Up next for Mr. Djokovic is 15th seed Holger Rune, who advanced after a five-set marathon against Quentin Halys. 鈥 Reuters