The ‘Drive for 25’ is over for Novak Djokovic at the Australian Open.

The 37-year-old Serb retired from his Australian Open semifinal with Alexander Zverev after losing the first set 7-6(5). Some of the crowd booed after Djokovic netted a forehand volley on set point and then walked to the net to shake hands with Zverev.

No. 2 Zverev will meet the winner between No. 1 and defending champion Jannik Sinner and No. 21 Ben Shelton in Sunday’s final. The German is 0-2 in Slam finals.

Djokovic, the 24-time Grand Slam champion, entered the match with tape around his left upper thigh area after suffering an injury in his four-set quarterfinal victory over Carlos Alcaraz. He didn’t practice for two days after the quarterfinal and then hit for about 40 minutes ahead of the semifinal.

“We could see him laboring but I don’t think we really knew how much he was suffering out here,” Patrick McEnroe said on ESPN.

“This hurts all of us, to see him go out like this….I can’t believe some people are booing, that’s just bogus. Some people are booing and Novak is putting his thumbs up.”

Speaking to the crowd on court, Zverev said, “The very first thing I want to say is, please guys, don’t boo a player when he goes out with injury. I know that everybody paid for tickets and everybody wants to see a great five-set match and everything, but you gotta understand, Novak Djokovic is somebody that has given this sport for the past 20 years absolutely everything of his life and he has won this tournament with an abdominal tear, he has won this tournament with a hamstring tear.

“If he cannot continue a tennis match, it really means that he cannot continue a tennis match so please be respectful and really show some love for Novak as well.”

Djokovic, who had won 23 of his previous 25 Grand Slam semifinals and is a 10-time Australian Open champion, said ahead of the match, “I am concerned, to be honest, physically.”

Djokovic failed to win a major in 2024 after capturing three in 2023, although he did win an elusive Olympic gold medal at the Paris Olympics last year. He brought on Andy Murray as his coach through the Australian Open, but now exits the tournament without a record 25th title.

“There’s no guy on tour I respect more than Novak,” Zverev said. “He’s been one of my closest friends. Whenever I struggled, I could always call him. I have nothing but respect for him.”