Cramp-stricken Jakub Mensik collapsed on court in distressing scenes after winning his second-round match at the French Open.
An unseasonal heatwave in Paris has made conditions tough for players during the first four days at Roland Garros and 26th seed Mensik was left in real trouble after battling to a 6-3 2-6 6-4 1-6 7-6 (13/11) victory over Mariano Navone in an epic four hours and 41 minutes.
Mensik was clearly cramping in his legs before serving the final point but managed to hit a final forehand winner before dropping to the clay.
The 20-year-old Czech, who was the last man to beat world number one Jannik Sinner in Doha in February, then lay on the court for several minutes, unable to get up.
He was attended to by medical staff, who placed ice towels around his neck and chest and an ice pack on his forehead before eventually helping him to his feet.
Mensik walked off court but had only taken a few steps back towards the locker room when he again looked close to collapse and he was placed in a wheelchair.
FRENCH OPEN FIXTURES AND RESULTS
Temperatures have been in the mid-30s all week and Roland Garros' outside courts in particular offer virtually no shade.
Former finalist Casper Ruud felt he was approaching heatstroke during his first-round match on Monday against Roman Safiullin.
The Norwegian eventually managed to recover and reach the second round, but he said afterwards: "I felt at times really dizzy and just really tired and walking around like a zombie almost."
Temperatures are not expected to cool in Paris until Sunday, with some rain forecast in the second week.
Meanwhile, Novak Djokovic (above) was booed by the crowd during a gruelling second-round win over Valentin Royer.
The third seed repeatedly expressed displeasure with the crowd making noise during points and in between serves.
When he saved a break point at a crucial moment in the fourth set, Djokovic put his finger to his lips in the direction of the home fans, earning loud jeers.
The 39-year-old also clearly did not enjoy playing in the heat of the afternoon on Court Philippe Chatrier, but he lived to fight another day after winning 6-3 6-2 6-7 (7) 6-3 in three hours and 44 minutes.
"It's a very important victory," said Djokovic. "The conditions are difficult for players. I had chances in the third set and it was my fault because I was twice a break up.
"It’s normal to have a few complications. I hope I won’t play against any other French players. That’s enough. I’ve played two matches and I feel like I’ve played two weeks.
"When I had a match point in the tie-break I was too passive and he took advantage. It’s very, very hot, but I’m happy to get through."
Djokovic claimed a 30th consecutive win against French players when he defeated Giovanni Mpetshi Perricard in round one, also dropping a set.
He turned that contest around after a tricky start and initially had few problems against Royer as he sought to reach the third round here for a 21st consecutive year.
Djokovic twice led by a break in the third set but both times Royer, ranked 74 and bidding for a first top-10 win, pegged him back straight away before delighting the home fans by saving a match point and winning the tie-break.
One break in the fourth set ultimately proved enough for Djokovic, although not before Royer had saved three more match points, one with a brilliant half-volley.
The Serbian will next face young Brazilian star Joao Fonseca in what will be a hugely anticipated first career meeting.
Fonseca, 19, was in tears after fighting back from two sets down against fellow youngster Dino Prizmic to win 3-6 4-6 6-3 6-1 6-2.
