Alex de Minaur could not be deflected by either rain showers or a determined compatriot as he began his assault on Wimbledon's grass citadel with a straight sets victory.
James Duckworth provided obdurate opposition, but despite forcing a trio of tie-breaks, Australia's No.8 could not take a set off the national No.1.
With his Davis Cup captain Lleyton Hewitt watching on, de Minaur won 7-6 (7-1) 7-6 (7-3) 7-6 (7-4).
A few yards away on the swathe of outside courts another Australian also progressed. Alexei Popyrin defeated Thiago Monteiro in four sets in just over two-and-a-half hours.
Adam Walton followed them into the second round with a straight sets victory over Federico Coria, his first ever grand slam win.
But two Aussie men went out, Rinky Hijikata and Chris O'Connell, while there were also defeats for Ajla Tomljanovic and Olivia Gadecki, leaving Daria Saville as the last Australian woman in the singles.
While the dogged Duckworth gave de Minaur a useful work-out, his resistance will have been frustrating. Combined with the inclement weather it kept the ninth seed occupied for much of the day.
Beginning at 11am local time (8pm AEST Tuesday) the match did not finish until nearly 4.30pm despite taking barely three hours to play.
One shower arrived just after de Minaur had taken the first set, the second with the third-set tie-break poised at 2-0 to de Minaur.
When they returned, around an hour later, de Minaur sealed victory within five minutes, Duckworth going long on the third match point.
Duckworth had his chances. He broke in all three sets, and had served for the second set at 5-4 and the third at 5-3. But both times de Minaur showed his class to break back.
"It's never easy playing a fellow Aussie, playing Ducks who's a great grass court player," said de Minaur.
"I knew that going in. It's one of those matches that could have easily have turned on its head."
De Minaur now plays 63-ranked Spaniard Jaume Munar. De Minaur has won all three previous meetings, including in straight sets at Roland Garros recently.
Walton's Wimbledon debut began in impressive style. The 25-year-old Queenslander ignored the rain breaks to beat the higher-ranked Coria 6-3 6-3 7-5 in just over two hours. It was his maiden grand slam victory.
"It feels very good," said Walton. "This is my third crack at trying to win a grand slam match, and to finally get over the line and get the win today, I'm over the moon.
"I saw the draw and I was like, 'Okay', when I saw I was not playing a seed. I was very happy about that."
But he will avoid a seed in the next round too, facing Argentine debutant, Francisco Comesana, who stunned No.6 seed Andrey Rublev in the first round.
"I'd rather play this guy than Rublev for sure," said Walton.
Popyrin had wrapped up his victory just before the second rain break arrived, beating Brazilian Monteiro 6-4 6-7 (8-10) 6-3 6-4.
It was his second win in Wimbledon's main draw in five visits, the last coming back in 2019.
He now faces another South American, Argentina's Tomas Martin Etcheverry.
Seeded 30, and ranked 16 places higher than Popyrin, the 24-year-old will be a much tougher test.
Tomljanovic followed de Minaur and Duckworth onto Court 12 but those Australian fans who stayed to watch were given little to cheer. The former Aussie No.1 lost 6-1 6-2 to Jelena Ostapenko and there were no sign of the sparks that featured in her ill-tempered meeting with the Latvian at SW19 in 2021.
Debutant Gadecki then lost too, 6-4 6-4, to fellow US qualifier Robin Montgomery.
As dusk fell, Hijikata was edged out by Flavio Cobolli 7-5 4-6 6-4 6-4 while O'Connell never got going against in-form 13th seed Taylor Fritz until it was too late, losing 6-1 6-2 6-4.
The fading light forced the suspension of Thanasi Kokkinakis' match with 17th seed Felix Auger-Aliassime.
Kokkinakis has already saved four match points but still has work to do at two sets to one down, and one game all in the fourth.
