Thanasi Kokkinakis is hitting his straps at just the right time, notching another underdog win ahead of next week's Australian Open.
The Australian played through three tie-breaks before defeating No. 2 seed and world No. 24 John Isner on Wednesday.
It took two hours and 42 minutes for Kokkinakis to prevail in the 6-7(5), 7-6(5), 7-6(4) victory.
The result sends him through to the quarter-finals of the Adelaide International, where he will face fellow Australian Aleks Vukic.
It also represents the 25-year-old's second-straight win over a top-50 ranked player, comfortably defeating Frenchman Benoît Paire in the round prior.
In an entertaining and even encounter, neither Kokkinakis nor Isner had their serve broken all match.
A tie-breaker was required after every set to separate the pair.
Although Isner served 25 aces to Kokkinakis' 15, it was the American's 31 unforced errors that were most pivotal, compared to the Australian's 14.
Speaking after the match, Kokkinakis explained that dealing with his opponent's strong serve was a serious challenge.
"Playing him is not fun," Kokkinakis said.
"I've had a few frustrating things in life, but that one's up there for sure.
"You feel like you're walking side to side.
"I just had to take my chances, I didn't in the first set and I thought maybe I had created the most chances in the first set, but I had to keep a clear head.
"It ends up being about, 'How do I distract him without being an idiot?'.
"I was trying to stand on the fence, stand close, I don't know.
"That's why he's so good and [has] been so good for so long.
"I just had to hope he'd miss a first serve, or if he jagged one, somehow return and be really sharp after that."
The current world No. 145, Kokkinakis has been handed a wildcard into the main draw of the Australian Open this year.
His giant-killing tendencies will undoubtedly make him a threat at Melbourne Park, as he aims to take advantage of his current hot form.
The Australian's highest ranking was world No. 69 six years ago, but his progress has been impacted by a variety of injuries since.
His five-set loss to Stefanos Tsitsipas in the second round of last year's tournament was a reminder of his potential as a player.
2022 could be another chance to make a memorable Australian Open run.