Jakub Mensik said his body "just turned off" as he collapsed on court following a gruelling second-round win in sweltering conditions at the French Open.

Temperatures reached the mid-30s in Celsius as the heatwave in France continued.

Mensik, 20, was overcome with emotion and cramp as he fell to the floor after beating Argentina's Mariano Navone 6-3 2-6 6-4 1-6 7-6 (13-11) in four hours and 41 minutes.

The Czech - whose flashes of brilliance in his young career have been beset by injury - was struggling to move and needed eight match points to close out victory.

After he fell the floor, opponent Navone crossed the net to congratulate him and also help him up, but Mensik was unable to move.

The 26th seed lay on the floor for several minutes and was attended to by several medical staff, who placed ice packs on his head, neck, and chest to help.

An ice pack was also laid on the floor for Mensik to rest his head on like a pillow.

Eventually, Mensik was helped to his feet and was able to walk off court, only to struggle again as he headed towards the locker room.

He was then placed in a wheelchair and taken away - although he told the media afterwards that he had been in an ice bath and done a recovery session in the gym as he starts his preparation for a third-round meeting with eighth seed Alex de Minaur on Friday.

"When I hit the last winner, the emotions went out and my body just turned off," Mensik said.

"It's insane to play in this weather and especially in front of the sun, to be there for more than four and a half hours is just insane.

"Even with the breaks, you don't have that much time. The ball kids can't bring your towel and during the changeover you have just one minute. Before you sit it's already 30 seconds and there's not that much time to cool yourself down."

Mensik, who was competing on one of the outer courts at Roland Garros which offer no shade, also said he was unhappy at being penalised for taking too long between points and twice lost his first serve as a result.

Elsewhere, three-time former champion Novak Djokovic faced Frenchman Valentin Royer on Court Philippe Chatrier, which has a roof, and was on court for three hours and 44 minutes.

The 39-year-old Serb lost a tight third set on a tie-break but regrouped to win 6-3 6-2 6-7 (7-9) 6-3.

In his post-match press conference, Djokovic suggested scheduling matches at Grand Slams later in the evening could be "something to consider" as a potential alternative if extreme conditions are expected.

French Open organisers monitor the temperature through two wet bulb sensors - one on Chatrier and another on Court 14.

If the threshold is reached, a 10-minute break may be introduced after the second set of women's matches and the third set of men's matches.

If temperatures continue to rise, matches can be suspended until the heat drops.

No French Open match has ever been halted because of extreme heat.

Women's 15th seed Marta Kostyuk said the conditions so far this week are not quite as bad as those she experienced when playing at the same venue for the Olympics in 2024, but added, "It's still hot and it's very dry. I always felt like I needed to drink, I want to drink more and more. It was tough."

On Monday, former finalist Casper Ruud said he felt he was "walking around like a zombie" and feared he had heat stroke after struggling with cramping in 33C temperatures.

One player who escaped the worst of the conditions on Wednesday was men's second seed Alexander Zverev, who played in the night session when temperatures had dropped to about 18C.

A runner-up at Roland Garros in 2024, Zverev continued his bid for a maiden Grand Slam with a dominant display to beat Czech player Tomas Machac 6-4 6-2 6-2 in one hour and 48 minutes.