American eighth seed Ben Shelton beat Ugo Humbert 6-3 7-6(2) 7-6(5) in an engrossing battle of lefthanders at Rod Laver Arena on Tuesday to reach the second round of the Australian Open.
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Shelton, who lost to eventual champion Jannik Sinner in last year's semifinals, relied on his power to blast through the first set but the Frenchman fought back from a break down twice in the second.
Shelton reasserted himself in the tiebreak, however, as his opponent's razor-sharp returns deserted him and he made several errors.
The third set was neck and neck all the way, with Humbert taking a 3-0 lead in the tiebreak before Shelton clawed his way back to book a spot in the second round.
FONSECA BROUGHT BACK TO EARTH AT AUSTRALIAN OPEN
Roger Federer said before the Australian Open that the "sky's the limit" for exciting Brazilian teenager Joao Fonseca, but he was brought back to earth Tuesday with a first-round exit.
The 28th seed, who won titles in Basle and Buenos Aires last season to signal his potential, crashed out 6-4, 2-6, 6-1, 6-2 after struggling physically against American Eliot Spizzirri.
The 19-year-old has been dealing with a back issue, which forced him to pull out of warm-up events in Brisbane and Adelaide.
"I don't regret a thing," he said of coming to Melbourne despite not being fully fit.
"I wasn't playing 100 per cent, but at the same time it gives me maturity to keep going, to understand my body, to understand my limits.
"Hopefully I'm still young and I'm still getting experience from that."
Fonseca made his big breakthrough at Melbourne Park last year as a qualifier when he beat top-10 player Andrey Rublev.
"My back is 100 per cent, I'm healthy again," he said. "I just needed time. I just need rhythm.
"I think this season is going to be great for me," he added.