Denis Shapovalov was not even sure if he would make the Australian Open after falling ill with Covid -- now he's into the quarter-finals and a meeting with Rafael Nadal.
The 14th seed from Canada sent Germany's world number three and Olympic champion Alexander Zverev tumbling out in the fourth round, winning in straight sets, 6-3, 7-6 (7/5), 6-3.
It set up a prized quarter-final with 20-time Grand Slam champion Nadal, with the top half of the men's draw opening up following the deportation of world number one Novak Djokovic.
But it could have been all very different for the 22-year-old Shapovalov.
He came to Australia infected with the virus and doubted whether he would play in the lead-up ATP Cup event in Sydney and the year's first major in Melbourne.
"There were a lot of doubts once I got to Australia with the quarantine, having gotten Covid, not sure how I would take it, not sure I would be able to play in the ATP Cup," Shapovalov said.
"After coming out of quarantine and playing the ATP Cup, I had a little bit of doubt, wasn't ready to play the first match and worked my way through the tournament.
"I started to feel back to normal towards the end of that week."
Shapovalov and Felix Auger-Aliassime played leading roles as Canada won their first ATP Cup title, against Spain, earlier this month.
Shapovalov said he had some aches and wasn't feeling the best when he arrived in Melbourne to prepare for the Australian Open.
"I wasn't practising that much, to be honest, and just trying to prepare the body as best as possible," he said.
"I'm just really happy with where I am in terms of my game, in terms of the level right now."