Men's 14th seed Denis Shapovalov survived a five-set marathon against Soonwoo Kwon on Wednesday, the Canadian needing four hours and 25 minutes to prevail 7-6(6) 6-7(3) 6-7(6) 7-5 6-2 at Margaret Court Arena.
The encounter was the third-longest men's singles match of the tournament to date, and Shapovalov improved his five-set win-loss record to 8-5 with the victory.
"Probably going to sleep in the ice bath tonight," Shapovalov joked afterwards.
"I played quite a few five-set matches leading up to this one, so I knew exactly when to press, when to kind of not go for it or not push," he added.
"I felt his belief slip away a little bit after the fourth set, so I definitely tried to take advantage of that."
The talented left-hander said he was pleased at his resilience and maturity.
"I did a good job of just flipping the script, kept fighting … really happy to get away with it," Shapovalov said.
"I think for sure two, three years ago I lose that fourth set and I lose the match, most definitely. But there's only one thing you can do [in] that situation when things aren't going your way, and that's to fight and to try to give everything you have."
Shapovalov is currently ranked 14th in the world, four rungs below a career-best No. 10 after reaching the Wimbledon semifinals last year, his career-best effort at a major.
During the off-season, he joined forces with former British pro Jamie Delgado, the long-time coach of five-time Melbourne Park finalist Andy Murray.
"From the moment we started, it's been really great. I feel like he's been listening to me a lot and learning about me, learning the way I am, and I'm also figuring him out as well," explained the No. 2 Canadian, who helped his nation to ATP Cup glory last week.
"He's been at the top with Andy, so he's got a lot of great experience and it's definitely something I can use and learn from," added Shapovalov, who trained with Delgado for a week before making his way Down Under.
"It's very early on, but I think we get along really well. I took Jamie in to clean up my net game. Obviously he was very good at the net himself, so for sure I felt like he could help me there.
"Movement-wise and experience-wise as well … he's been with Andy through the big moments and it's just learning from him and working on how to prep for slams and how to prep for big events."
To earn a maiden fourth round Australian Open appearance, Shapovalov must navigate past Laver Cup doubles teammate Reilly Opelka. The two have not faced off since 2017, when the Canadian needed three sets to get past the 211cm American in qualifying at the 2017 Queen's Club Championships.
"It's going to be tricky," said Shapovalov of Opelka, seeded 23rd this fortnight.
"He's a big guy, obviously [a] big server, so it's going to be a lot of guessing from my end and just kind of trying to take my opportunities when I get them."