Championship leader Kimi Antonelli pulled out all the stops on his final lap to snatch pole position for the Monaco Grand Prix from Max Verstappen.
The 19-year-old Italian in the Mercedes beat the Red Bull four-times world champion by just 0.043 seconds on Saturday. Ferrari's Lewis Hamilton was third quickest.
Starting from the very front of the grid is a big advantage through the winding streets of the glamorous principality, where overtaking is notoriously difficult.
Antonelli, fastest in final practice earlier on Saturday, picked up his fourth pole of a burgeoning career having won the last four races.
The teenager said: "It was one of those laps we call the magic lap, I was able to put it all together. It was so close with Max, the first run there was just one millisecond. Massive thanks to the team as yesterday we struggled a little bit and today we improved massively."
Verstappen has hinted at quitting F1 given new technical rules this year which he feels have made the sport less fun. But the Dutchman, seventh in the standings, was in an upbeat mood on Saturday.
"If you would have told me yesterday front row, I would definitely have taken it. It is extremely positive, so overall very happy with how the laps went," he said.
"I'm happy, happy to be on the front row and let's see tomorrow. These cars are complicated to start and I have two cars behind me that start quite well."
Ferrari, who had topped the timesheets in Friday practice, were without team boss Fred Vasseur for qualifying due to health problems.
The team said the 58-year-old Frenchman was staying under observation at a clinic without specifying his ailment.
Kardashian cheers on Hamilton
The sun was shining on the yachts, casino and packed stands in Monaco, where Hamilton had a notable fan. His girlfriend, reality TV star Kim Kardashian, turned up to watch him for the first time.
The British seven-times champion finished ahead of team-mate, Monaco-born Charles Leclerc, who was fourth fastest.
Hamilton added: "Congrats to Kimi, mega, mega job - first pole here is so special. It was tough for us, we were looking so strong in practice, we hardly changed anything but the car was completely different in Qualifying. But what a privilege to be one of the 22 drivers here able to do this.
"I think it's great to see how close all the cars are. We lost something going into today, so we need to try and figure that out."
Antonelli is 43 points ahead of team-mate George Russell at the top of the drivers' standings. Briton Russell, who won the opening race in Australia before fading, was only sixth in qualifying behind Isack Hadjar.
World champion Lando Norris was eighth fastest in his McLaren, just behind team-mate Oscar Piastri. Pierre Gasly and Liam Lawson round out the top 10.
Audi's Gabriel Bortoleto crashed on the tight course in Q1 to dash his hopes of the top 10 as he was eliminated in Q2 without a time.
British Haas driver Oliver Bearman went out in Q1 after a crash in practice left his mechanics with a tight window to fix his car.
Sunday’s 78-lap Monaco Grand Prix is the sixth of 22 rounds, assuming the cancelled races in Saudi Arabia and Bahrain are not held later in the year.
