The 89th-ranked Ben Shelton admitted Monday he was more surprised than anyone with his run to the Australian Open quarter-finals, on his first time outside the United States.
The 20-year-old became only the fourth man in the past 20 years to reach the last eight on debut in Melbourne and will play fellow American Tommy Paul for a place in the semi-finals.
Shelton prevailed 6-7 (5/7), 6-2, 6-7 (4/7), 7-6 (7/4), 6-2 in sapping heat against JJ Wolf in another all-American clash to reach the quarter-finals in only his second Grand Slam.
"Definitely a surprise," said left-hander Shelton, who a year ago was at the University of Florida and ranked 569 in the world.
"I got on the plane with no expectations. I know that it's very hard to adjust to Australia from the United States just with the jet lag, time change and everything.
"It being my first time, never being out of the United States, I knew it would be a struggle.
"So I think it maybe has helped me a little bit kind of not having that expectation or the feeling that I have to perform, but being able to just go out there, be myself and play free," he added.
"I think that's been a big contribution to my success."
By making the last eight, Shelton joined just three other men to get that far in Melbourne on debut over the past two decades -- Ukraine's Alexandr Dolgopolov (2011), American Tennys Sandgren (2018) and Russian Aslan Karatsev (2021).
In his only previous Grand Slam appearance, as a wildcard at the US Open last year, Shelton crashed out in the first round.
- 'Courageous' -
Nothing separated him and his friend Wolf in the opening set, with Shelton's one break point the highlight as it went to a tiebreak.
Ultimately, Wolf's power-hitting got him over the line at a scorching John Cain Arena.
Set two also began as a battle of small margins, but Shelton got the first break of the match in game six when Wolf netted a volley then slapped a forehand wide, breaking again as Wolf began wilting in the afternoon heat.
Wolf removed his shoes and left the court at the changeover, returning with new attire and footwear.
In a virtual carbon copy of the opening set, it went to a tiebreak where Wolf again prevailed.
Shelton then took the fourth in another narrow tiebreak before putting his foot to the floor in the fifth.
"It was definitely a gruelling match. There were a lot of swings throughout the match," he said.
"I really focused in the fifth set, just being energetic, trusting my fitness and just hustling, being courageous."
Paul defeated Spanish 24th seed Roberto Bautista Agut 6-2, 4-6, 6-2, 7-5 to also reach a first Grand Slam quarter-final.