Australian tennis's most improved performer recovered from a labouring start to post a 3-6 7-6 (7-2) 6-4 7-5 win over Hungarian qualifier Mate Valkusz at Kia Arena.
Purcell was the first local winner on day three, joining Alex de Minaur, Alexei  Popyrin, Jordan Thompson, Chris O'Connell and Storm Hunter in the second round after posting his maiden main-draw victory at Melbourne Park.
The 25-year-old had previously crashed out in round one in 2020 and 2023.
But those were the days when the Sydneysider was regarded more as a doubles specialist.
Twice an Australian Open doubles runner-up and Wimbledon doubles champion in 2022 with Matt Ebden, Purcell has morphed into a singles player of real substance.
He soared to No.40 in the world after reaching the Cincinnati Masters quarter-finals in August and is currently ranked No.45, making him Australian No.3 behind only de Minaur and Popyrin.
Despite a gulf of 169 rankings spots, Purcell didn't exactly do it easy against Valkusz, struggling for much of the first two sets to find his rhythm and then blowing six match points before finally prevailing after two hours and 52 sweat-soaked minutes.
"I was kind of just like 'turn it up', to be honest. The guy was pummelling me," Purcell told the courtside crowd.
"I didn't really stand much of a chance there, snuck my way back in the second set.
"Just tried to hold onto my serve and then hope he'd crack and he cracked and I got through it.
"I definitely needed you guys' support deep in the fourth. I was gagging it so hard."
He next plays Norwegian 11th seed Casper Ruud for a place in the last 32 of a grand slam for the first time.
"I played (and beat) Casper in Cincinnati in relatively lively conditions. The ball's a little lighter than and more bouncy," Purcell said.
"But it's hot here, I'll have the crowd on my side and I'm more than happy to give him another crack."
Purcell aside, it wasn't a great start for the local contingent, with Olivia Gadecki crashing out in less than an hour and fellow wildcards Kim Birrell and James McCabe also removed.
Gadecki was unable to emulate her first-round victory as a wildcard last year, falling 6-3 6-1 to American Sloane Stephens in 56 minutes on John Cain Arena.
Olivia Gadecki couldn't go the distance with Sloane Stephens. (James Ross/AAP PHOTOS)
The 21-year-old made a flying start, breaking Stephens to love and winning the opening eight points of the match.
But from 2-0 up, Gadecki fell apart, winning only seven more points to drop the set with a flurry of unforced errors.
Continuing to press in the second set against the clean-hitting former US Open champion, Gadecki only managed to win one more game as she finished with 26 unforced errors to Stephens' seven.
Birrell offered more resistance in a 7-6 (7-5) 6-1 loss to Latvia's in-form world No.10 Jelena Ostapenko, last week's Adelaide International champion.
McCabe was also gallant in a 7-6 (7-5) 3-6 6-1 6-2 loss to American Alex Michelsen on the 20-year-old's grand slam debut.
James McCabe bowed out in four sets to American Alex Michelsen. (James Ross/AAP PHOTOS)
Three-time grand slam quarter-finalist Ajla Tomljanovic was scheduled to make her first appearance at the Open in two years on Tuesday night, following the completion of countryman Thanasi Kokkinakis's first-round clash with Austrian Sebastian Ofner.
Tomljanovic takes on Croatian Petra Martic in the night session after missing last year's tournament with a knee injury.
Kim Birrell and Thanasi Kokkinakis also feature later.
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