Russell's pole lap was nearly eight-tenths of a second quicker than third-fastest Isack Hadjar's Red Bull, underlining Mercedes' promising form during winter testing.
While Red Bull's four-time world champion Max Verstappen crashed out and McLaren's defending champion Lando Norris fretted about his car after posting the sixth-quickest lap, Russell was pleasantly surprised by his car's performance.
"I think we’ve got a really great engine beneath us," the Briton said after taking Mercedes' first pole in Melbourne since Lewis Hamilton in 2019.
"However, I think we’ve also got a really amazing car beneath us, and I think that probably hasn’t been highlighted enough in the press these past few weeks.
"I think the car, from the off, Kimi and I both said it felt great to drive. We're enjoying the smaller cars, the lighter cars."
Russell said the new way of racing was still a challenge, with the car behaving more like a go-kart compared to last year's "bouncing bus".
"The cars are more agile and you’re sort of sliding them around a bit more," he said.
"It’s easier to lock up and run wide, lose the rear.
"So I think there are lots of mixed views on the new regulations as a whole, but I do think the car regulations for everyone are definitely a step forward compared to what we’ve had for the past, what, eight years now."
Antonelli faces a nervous wait for his position to be confirmed, with stewards investigating Mercedes for releasing his car in an unsafe condition.
The 19-year-old Italian's car suffered heavy damage in a crash in final practice and needed extensive repairs before qualifying.
His car then dropped cooling fans on the track to trigger an early red flag in the final session of qualifying, with Norris running over one of them in his McLaren, causing a crack in his front wing.
"We couldn’t even set up the car, we just went out and managed to put it on the front row. So really happy with that," said Antonelli.
Team boss Toto Wolff lavished praise on Antonelli for shrugging off the crash but stopped short of saying he could fight Russell for the championship.
"I think in pure speed terms, he's absolutely there," said Wolff.
"He was quick all weekend, quick until he went off in the morning. And I think it's a miracle that not only the car was put together, but also the lap that he did.
"There was no set-up on the car, we were never able to really measure it. He's from the raw speed, from the talent, from his ability, absolutely.
"But he's in his second year of Formula One, George is nine or 10. All around you need experience, so I think it would be early days for Kimi to compare himself to George."
