Novak Djokovic has withdrawn from a US Open tuneup tournament in Montreal after his victory over Rafael Nadal at the Paris Olympics.

Djokovic, 37, beat Nadal in straight sets on Monday at Roland Garros to reach the third round at the Summer Games.

Djokovic had been planning to play in the National Bank Open, an ATP Masters 1000 event that begins Aug. 6. The tournament announced his withdrawal.

Djokovic has won a record 24 Grand Slam singles titles but has never won Olympic gold.

“While we’re disappointed that Novak will be unable to take part in this year’s tournament, we understand his decision and wish him the best at the Olympics and the remainder of his season,” National Bank Open tournament director Valerie Tetreault said.

Roman Safiullin took Djokovic’s spot in the main draw.

Carlos Alcaraz reaches third round, injures groin at Olympics

Spain’s Carlos Alcaraz defeated Netherlands’ Tallon Griekspoor 6-1 7-6(3) on Monday to reach the third round of the Paris Games tennis tournament as he strives for Olympic gold.

The world number three, who won this year’s French Open and Wimbledon titles was back on Court Philippe-Chatrier and set the tone from the start with an ace and two forehand winners.

With the crowd having seen fellow Spaniard Rafael Nadal beaten by Novak Djokovic, Alcaraz appeared determined to show he was ready to take up the baton at Roland Garros, breaking Griekspoor immediately and racing through the first set in 32 minutes.

But the Dutchman, ranked 28 in the world, made a better fist of it in the second set. Griekspoor repeatedly held his serve under pressure, giving back as much as Alcaraz threw at him and at times forcing the Spaniard into some uncharacteristic errors.

Alcaraz needed a medical timeout for treatment from a trainer for a groin muscle issue in the second set. He was a point from getting pushed to a third set in a tiebreaker, but he finished the job.

“It’s a pain that I’ve been dealing with,” Alcaraz said, mentioning that it bothered him during his run to the Wimbledon championship this month. “I know what I have to do … to deal with this pain.”

In the singles third round, Alcaraz will play Russian Roman Safiullin, the world number 67, who is competing as a neutral athlete. Alcaraz is also scheduled to play doubles with Nadal on Tuesday against Griekspoor and Wesley Koolhof.

“I will try to recover as soon and as (best) as I can tonight,” Alcaraz said, “to be … 100% tomorrow in my doubles.”

The Associated Press and Reuters contributed to this report.