Denis Shapovalov stunned himself as he swept aside world No.3 Alexander Zverev to set up a blockbuster Australian Open quarter-final showdown with Rafael Nadal.
The 22-year-old has reached the last eight at a grand slam for a third time, less than a month after a positive COVID-19 test on arrival in Australia threw his preparation into disarray.
Shapovalov recovered to help Canada lift the ATP Cup title in Sydney, laying the groundwork for what has developed into a seven-match winning streak.
The Wimbledon semi-finalist and Open 14th seed is now revelling in his deepest run at Melbourne Park, following a 6-3 7-6 (7-5) 6-3 victory over Olympic gold medallist Zverev in scorching conditions on Sunday.
"I started to feel back to normal towards the end of that week (in Sydney), so it was a good sign, then coming here I had a couple of aches and wasn't feeling 100 per cent physically," Shapovalov said.
"I wasn't practising that much, to be honest, and just trying to prepare the body as best as possible.
"I'm just really happy with where I am in terms of my game, in terms of the level, right now."
Nadal presents another huge hurdle.
The Spanish great has dropped just one set in four matches at the Open and continued his impressive form in a 7-6 (16-14) 6-2 6-2 victory over France's Adrian Mannarino.
The pair played some of the best tennis of the tournament in the first set, clinched by Nadal in a marathon tiebreak after 81 minutes.
The 20-time grand slam title winner then settled in and found his rhythm.
"Everybody knows how mental is this game - it's a tough one," a relieved Nadal said.
"That crazy first set, I think, was so important and the beginning of the second.
"He had been playing some fantastic tennis during the whole tournament, winning against amazing players like (Aslan) Karatsev and (Hubert) Hurkacz.
"Today the first set was super difficult, his ball was very difficult to control, very flat, very fast and I am very happy that I survived that first set without a doubt."
No.17 seed Gael Monfils beat Miomir Kecmanovic 7-5 7-6 (7-4) 6-3 to end the Serb's surprise run and tee up a quarter-final clash with Matteo Berrettini.
Kecmanovic was due to play countryman Novak Djokovic in the first round and after the world No.1 was deported, fought through to his best grand slam result, but couldn't get past Monfils, who is yet to drop a set.
Monfils also benefited from the defending champion's absence, given his 0-17 record against Djokovic and will attempt to reach the Melbourne Park final four for the first time.
Wimbledon finalist Berrettini fired down 28 aces in a disciplined 7-5 7-6 (7-4) 6-4 victory over No.19 seed Pablo Carreno Busta.
In the process, the world No.7, who had to pull out of his 2020 Melbourne Park fourth-round match with an abdominal injury, ensured he'd reached the quarter-finals of all four grand slams.
