The physicality of facing Rafael Nadal in a best-of-five-set match can cause suffering even in the fitness opponents.
Staring down a dire two-set deficit to Nadal, Stefanos Tsitsipas reached a state of personal nirvana to rally.
Nadal: If We Stop the Sport, People Will Suffer
The fifth-seeded Greek unleashed his all-court arsenal fighting off the 20-time Grand Slam champion 3-6, 2-6, 7-6(4), 6-4, 7-5 to reach his second Australian Open semifinal.
Tsitsipas joined Roger Federer and Fabio Fognini as the third man to battle back from two sets down and defeat Nadal.
What keyed his comeback?
Tsitsipas said thinking of nothing empowered him to throw everything at Nadal.
"The thing is that I wasn't really thinking about a lot of things," Tsitsipas told the media afterward. "Nothing was going through my head. How would I describe myself? Nirvana. Just, like, there. Playing, not thinking.
"I was thinking a little bit, but I was mainly focused on each single serve, each single shot. I think at the very third set I changed few things. I changed my patterns. I maybe took a little bit more time. I think that helped. I wanted to stay in the court a bit longer."
The instinctual approach helped Tsitsipas top Nadal for the first time in five meetings on a hard court thwarting the Spaniard's bit to capture his record-extending 21st Grand Slam title in Melbourne.
Ultimately, Tsitsipas used his wide serve, skill shifting spins and all-court game to earn a breakthrough win.
"I think the change the pace, the rhythm, things like this," Tsitsipas said. "I may have put my brain a little bit, I brainstormed and I said, What is going wrong, why is it not working my way?
"But then it just took off by itself. I didn't really have too much to think of. I think that's the way I feel it. I just played more flawless. I really didn't care, honestly. I played with no care, and that increased the level of tennis that I put out there."
Photo credit: Australian Open Facebook