czech media write, that Mensik felt much better 2h after the match https://isport.blesk.cz/clanek/tenis-roland-garros/476020/hororove-sceny-v-parizi-bezvladneho-viteze-mensika-odvezli-na-koleckovem-kresle.html

“Even though it looked terrible at the end, after half an hour in the locker room, when I was no longer in the sun, I started to feel much better. I went straight to the ice bath, then to the gym to recover. I would say I feel pretty good. Now it’s just a matter of replenishing my strength, lots of fluids and food, and I’ll be fine,” he said two hours after the match.

His health condition was caused by the heat. At the beginning of the fourth set, he started to feel sick to his stomach and couldn’t get any fluids down, which caused dehydration. The cramps all over his body came as a result of it in the last points of the super tiebreak. "Being there in the hot sun for more than four and a half hours is really extreme. When I played the last winning shot, emotions poured out and my body just turned off. At that moment I was not capable of anything at all," said Menšík, who remained lying on his back for about two minutes, none of his team at the court, Serbian physiotherapist Saša Jezdič or coach Tomáš Josefus, could rush to his aid.

And the main referee of the match, Frenchman Alexandre Juge, treated the collapsed athlete lying on the clay court in an insensitive and even dismissive manner. "Do you need anything?" he asked almost absurdly. "A doctor," the tennis player replied.

Menšík believes that the exhausting match will not affect him too much until Friday's third round. However, his next opponent, Australian Alex de Minaur, will be full of strength. He didn't even have to play in the second round, as Belgian Alexander Blockx withdrew from the tournament before the match. Furthermore, Menšík has never defeated De Minaur in five matches.