After Thanasi Kokkinakis won his first-round match on Monday, compatriots Purcell, Alex de Minaur and Aleksandar Vukic secured impressive straight-sets victories on Tuesday to join him in the tournament's last-32.
Qualifier Purcell enjoyed a 96-minute 6-4 6-4 success over fan favourite and 10th seed Felix Auger-Aliassime.
It was the Sydneysider's maiden win at ATP Masters 1000 level and a second victory against the Canadian world no.12, who he also beat at the 2021 Tokyo Olympics.
The 25-year-old broke in the opening game of the contest and again in the third game of the second set but the world No.78 was most dominant on serve - sending down eight aces, winning 90 per cent of his first serves and not facing a break point.
"These top guys haven't played me much, so they don't really know too many of my patterns yet," Purcell said in his on-court interview.
"I'm sure Felix will figure it out at some point and smoke me.
"But it's a little bit of that unknown and I have nothing to lose out here as well.
"In saying that, I still trust that my level is good enough to play with these big guys."
Purcell's win marks the highest-ranked victory of his career and he'll next take on three-time grand-slam champion Andy Murray, who defeated Italy's Lorenzo Sonego 7-6 (7-3) 6-0.
Earlier on Tuesday, Vukic recorded an equally stunning 6-2 6-3 triumph over Croatian 14th seed Borna Coric.
Currently enjoying a career-high ranking of 62, Vukic needed just 74 minutes to see off the world No.15 and set up a round-two match against American Sebastian Korda, who beat Argentina's Tomas Martin Etcheverry 6-3 6-2.
De Minaur's impressive hard-court form ahead of this month's US Open continued.
After losing last week's Los Cabos final in Mexico to Stefanos Tsitsipas, the world No.18 scored a 7-5 6-4 win over 11th seed Cameron Norrie to improve his head-to-head record with the British No.1 to 2-1.
The 24-year-old needed one hour 43 minutes to set up a last-32 clash with local Gabriel Diallo, who beat Dan Evans 7-6 (7-4) 7-5.
"It was definitely not easy conditions out here. It was blowing a gale, it didn't make for pretty tennis," De Minaur, the recently crowned ATP 500 Acapulco champion who is now 18-8 on hard courts for the season, told atp.com.
"We both struggled a bit out here today, but I'm happy I was able to get the win over an incredible opponent.
"I've always thought I've had this level, and now I've just put a couple of good matches together and that gives you confidence.
"You build on that, and hopefully we can keep it going."
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