Formula One leader Valtteri Bottas put Mercedes on pole position for the Spanish Grand Prix on Saturday with team mate Lewis Hamilton qualifying alongside in a front row lockout.
The pole was a third in a row for the re-energised Finn, who leads Hamilton by a single point after four of the 21 races, and he did it in a track record time of one minute 15.406 seconds.
That was a hefty 0.634 quicker than Hamilton's best effort, dashing the five-times world champion's hopes of record-extending 85th career pole.
Sebastian Vettel qualified in third place, in 1:16.272, with Red Bull's 2016 Spanish Grand Prix winner Max Verstappen fourth and sandwiched between the Ferraris, with Charles Leclerc fifth.
"I really enjoyed that, enjoyed the adrenaline rush you get from those laps so I'm really pleased," said Bottas.
"The season has started well, the way I hoped for and I feel better and better in the car so I look forward to tomorrow," added the Finn, who will be chasing his third win of the season on Sunday.
Hamilton said his laps in the final phase of qualifying could have been better, with a scrappy first effort kicking up gravel, but the upgrades brought by Mercedes to the start of the traditional European part of the campaign were working well.
The Briton, winner for the past two seasons in Barcelona and three times in all, said Bottas had simply been quicker on the day.
"Valtteri did a fantastic job, he's been quick all weekend," said Hamilton. "On my side, I just didn't put the lap together... ultimately it just wasn't a good enough job.
"It's great for the team to have this one-two so we'll try and convert that into a one-two (on Sunday) and if I can reverse it I'll be happy."
Mercedes have won the first four races one-two, a record start for any team, despite Ferrari setting the pace in pre-season testing.
"I think we got everything out of the car in the first run," said Vettel. "In the second run I had to try something different and it didn't work.
"The car doesn't feel bad but obviously we are not quick enough. In terms of balance we got it more or less right," added the German, who said Ferrari were still down on grip through the slower corners.
Red Bull's Pierre Gasly qualified sixth with the Haas pair of Romain Grosjean, yet to score a point this year, and Kevin Magnussen seventh and eighth on the grid.
Toro Rosso's Daniil Kvyat qualified ninth with Renault's Australian Daniel Ricciardo, who reversed into him at the previous race in Azerbaijan, 10th fastest.
Ricciardo has a three-place grid penalty for that embarrassing error in Baku, meaning that McLaren's teenage rookie Lando Norris will take the 10th place instead.
Carlos Sainz, the only Spanish driver in the race now that Fernando Alonso has left Formula One, qualified 13th for McLaren but will also move up a place.
Renault's Nico Hulkenberg failed to get through the first phase after running off the track and breaking his car's front wing.
"We damaged a new spec front wing so had to change to old spec," he said after pitting and returning to the track.