Double world champion Max Verstappen claimed pole on Saturday for the Australian Grand Prix ahead of Mercedes' George Russell, but his Red Bull teammate Sergio Perez had a torrid time and will start last.
In overcast and cool conditions, Lewis Hamilton in the other Mercedes was third ahead of Aston Martin's Fernando Alonso in a tight session that went to the wire.
Last year's winner Charles Leclerc came seventh in the Ferrari, with his teammate Carlos Sainz fifth.
It was a huge performance from Mercedes, whose W14 has struggled for speed but is clearly improving as they again bettered Ferrari.
Lance Stroll in the other Aston Martin will start sixth ahead of Leclerc with Williams' Alexander Albon a shock eighth.
Alpine's Pierre Gasly was ninth with Nico Hulkenberg in a Haas rounding out the top 10.
It was a second pole of the year for Dutchman Verstappen, and the 22nd of his career, after the season-opening race in Bahrain, which he went on to win.
He started from 15th in Saudi Arabia a fortnight ago after mechanical problems, but sliced through the field to come second behind Perez.
The 25-year-old knocked out his rivals with a flying lap at the death of one minute 16.732, which was 0.236 secs ahead of Britain's Russell.
"I think the last run was very good, the whole weekend has been tough to get the tyres in the right window," said Verstappen, who has never won in Australia and will start on pole for the first time at Albert Park.
"Very happy to be on pole, already looking forward to tomorrow. I think we have a good race car but it is tricky on the tyres, so going to be an interesting race for sure."
But Mexico's Perez – one point behind Verstappen in the championship standings – had a horror of a day, struggling with grip and balance.
He left the track four times during the third practice and it didn't get any better in qualifying when he locked up and careened into the gravel at Turn 3 on his first lap.
His car beached and had to be removed by a crane, with the session red flagged.
"It's really hard to digest this one," a dejected Perez, who blamed a technical issue, told reporters.
"To end qualifying on the second braking zone is really disappointing. But nothing I can do now. I have to look forward."
Russell, who came fourth in Saudi Arabia, was stunned with Mercedes' performance, saying "we weren't expecting that, that's for sure".
"What a session for us. The car felt alive, and to be honest I'm disappointed I didn't get pole as the car felt awesome," he added.
"We are learning more and more about the car, it's still not where we want it to be, but it's evolved from Bahrain to Jeddah to here.”
