The exact cause of Carlos Alcaraz's cramping, which he suffered during his French Open semifinal defeat by Novak Djokovic on Friday, will probably become fully apparent only in the days and weeks to come.
But one thing is for sure, the stress the 20-year-old felt in playing the 22-time Grand Slam champion, at the highest intensity, on a huge stage, was a hugely significant factor.
"[It was] the tension," Alcaraz told reporters. "The tension of the match. You know, I started [the] match really nervous. The tension of the first set, the second set, it was [a] really intense two sets. Really good rallies, tough rallies, drop shots, sprints, rallies. It's a combination of a lot of things. But, you know, the main thing, it was the tension that I had all the two first sets."
Alcaraz was brilliant in the latter stages of the second set, leveling the match to one set each, before his right leg cramped up at 1-1 in the third. The Spaniard said he "disappointed himself" with the manner of the defeat, and, to add insult to injury, he will now lose the world No. 1 ranking to Djokovic should Djokovic go on to win the title Sunday in Paris.
With temperatures reaching 86 degrees Fahrenheit, the two players pushed each other to the limit in the first two sets, which lasted two hours, 18 minutes. Alcaraz recalled a few moments in previous matches when he had struggled with cramps but said they were "not of this magnitude".
"I would say the first set and the second set was really, really intense, you know, and I started to cramp in my arm," he said. "At the beginning of the third set, I started to cramp every part of my body, not only the legs. The arms, as well, every part of the legs. Well, it was really tough for me to move at the third set, and in the fourth set, let's say I had a little chance, but it was really tough. You know, my full body [started] to cramp."
Djokovic is 16 years older than Alcaraz, and Djokovic's experience -- this was his 45th Grand Slam semifinal -- meant he was calm while Alcaraz appeared rattled right from the start.
"Is not easy to play against Novak, you know," he said. "Of course, a legend of our sport. If someone says that he gets into the court with no nerves playing against Novak, he lies. Of course, playing a semifinal of a Grand Slam, you have a lot of nerves, but even more with, you know, facing Novak. That's the truth. Next time that I'm gonna face Novak, I hope to be different, but the nerves will be there."
Commentating on the match for Eurosport, three-time Roland Garros champion Mats Wilander said Alcaraz's style of play means he expends more energy than Djokovic. "It was caused by Novak, only by Novak," Wilander said. "The difference between how Novak moves around, even when he's exhausted, and compared to Carlitos is a huge difference. I've never seen this from Carlos, and Novak exposed a weakness in him.
"I think there was tension and stress, for sure. I haven't heard him cramping before; I can't imagine he's not had a great preparation, so I think there was stress, for sure.
"Carlos Alcaraz ran an average of 20 meters up to his cramping part," he said. "They played 155 points, that's 3,000 meters, that's 30 x 100-meter sprints in two hours. He's not walking; he's sprinting for everything. Novak is smoother, and Carlos might not read the game as well and has taken way more steps."
Djokovic said he could understand why Alcaraz felt stressed.
"I have experienced that several times," he said. "Early in my career, I was struggling quite a bit physically. I can understand the emotions and circumstances that affect you mentally and emotionally.
"Being in one of the greatest tournaments of the world, maybe for the first time in his career he was expected to win. He was maybe not an underdog, chasing the title and trying to win against a favorite, but it was probably the other way around. So maybe that affected him, you know, and as he said, it probably did."