Top-ranked Carlos Alcaraz pulled out of the Australian Open on Friday because of an injured right leg.

The 19-year-old from Spain wrote on social media that he got hurt “through a chance, unnatural movement in training.”

The year’s first Grand Slam tournament begins on January 16 at Melbourne Park. The draw is on Thursday.

Alcaraz won the US Open last September and moved atop the ATP rankings. That allowed him to become the youngest man to finish a season at No. 1 since the computerised men’s tennis rankings began a half-century ago.

His rise from No. 32 at the end of 2021 also marked the largest single-season jump to No. 1.

This is his second significant setback in recent months, though. Alcaraz cut short last season in November after tearing an abdominal muscle while competing at the Paris Masters. That forced him to withdraw from the ATP Finals and Davis Cup Finals.

Still, he closed out 2022 with a record of 57-13 and five singles titles.

“I’d worked so hard to get to my best level for Australia but unfortunately I won’t be able to play, at a tuneup event in Kooyong or the year’s first Grand Slam tournament,” Alcaraz wrote on Twitter.

“It’s tough, but I have to be optimistic, recover and look forward,” he said.

With Alcaraz out, No. 2 Rafael Nadal — the defending champion in Australia and owner of a men’s-record 22 Grand Slam titles — will move up to No. 1 in the seedings for the hard-court tournament.

The Spaniards became the first players from the same country to claim the top two spots in the ATP at the close of a season since Americans Pete Sampras and Michael Chang in 1996.

Alcaraz’s departure also removes a potential hurdle for Novak Djokovic as he returns to Australia and tries to win it for a 10th time to claim what would be his 22nd major championship overall. Djokovic missed the 2022 Australian Open after being deported from the country because he was not vaccinated against Covid-19.

He is still not vaccinated, but restrictions have eased.

Rafael Nadal. File picture

Venus withdraws

Venus Williams also withdrew for an undisclosed injury she sustained while playing in a tournament in Auckland this week.

A seven-time Grand Slam singles champion, Venus received a wild-card entry into the tournament last month to compete in what would have been her 22nd major at Melbourne Park.

But the Australian Open said on Saturday the 42-year-old Williams had withdrawn. It did not provide specifics regarding the injury. It continues a run of misfortunes for Williams, who last played at Melbourne Park in 2021.

A two-time Australian Open finalist, Williams injured an ankle and knee in that appearance when stumbling awkwardly at the net in a second-round match against Sara Errani.

Her best efforts at Melbourne Park came when she was beaten by her sister Serena Williams in finals in 2003 and 2017.

Novak enters final

Djokovic beat Daniil Medvedev 6-3, 6-4 to advance to the Adelaide International final despite sustaining a leg injury during the match.

In the seventh game of the first set, Djokovic caught his left foot when sliding for a ball and immediately began stretching out his hamstring. He took a medical timeout.

Djokovic will play Sebastian Korda in Sunday’s final.