Stefanos Tsitsipas is defying doctors orders to be firing at the right end of the Australian Open as the world No.4 chases a maiden grand slam title.
The Greek star booked his place in the semi-finals at Melbourne Park for the third time in four years by demolishing Italian Jannik Sinner 6-3 6-4 6-2 in their last eight clash.
After looking shaky in his fourth-round match against Taylor Fritz, when the American pushed him to five sets, Tsitsipas looked at home on Wednesday.
The 23-year-old needed a little more than two hours to overcome Sinner, who was coming off a scintillating victory over Australian Alex de Minaur.
It was a major warning shot to the rest of the Open field, as Tsitsipas loomed as a pre-tournament favourite but had been unable to put together his best tennis until now.
After undergoing elbow surgery in November, Tsitsipas was unsure if he would even make it to the Australian Open.
"I'm pretty sure my doctor is watching right now - Frank has been sending me texts after every single game," Tsitsipas said.
"We both didn't expect for me to participate at the Australian Open, it was not part of our plan to be playing in Australia, but I've proved him wrong.
"Frank is a big tennis enthusiast and he's worked with a lot of tennis players and I'm happy I've found the right person to bring me back stronger."
Tsitsipas will face Russian world No.2 Daniil Medvedev or Canadian rising star Felix Auger-Aliassime in the semi-finals on Friday.
He is still searching for his maiden grand slam title after losing last year's French Open final to Novak Djokovic when he took the opening two sets from the world No.1.
Spanish legend Rafael Nadal is up in the other semi-final against Italian seventh seed Matteo Berrettini on Friday.