Fabio Quartararo claimed a fourth pole position in an impressive debut MotoGP season in Thailand as Marc Marquez once again came off his bike in Buriram.
Rookie Quartararo is becoming an expert at qualifying, setting a record for the fastest lap time at the track as he clocked one minute 29.719 seconds during the second session.
However, the Frenchman - still chasing his first race win - pushed too hard on his final attempt to go even quicker in Q2, resulting in him coming off his bike at turn five.
"It's never good to crash, but now we feel the limit. I was braking too much and I know where the limit is on the bike - that is really positive," Quartararo told BT Sport. "This pole position tastes even better than the other ones."
The same had also happened to Marquez - who had wrecked his bike on Friday when hitting the ground heavily in FP1. He came a cropper at turn five too, forcing him to settle for third place on the grid.
Still, the Spaniard appears on course to clinch a sixth world title on Sunday. He will be crowned champion yet again if he picks up two more points than nearest rival Andrea Dovizioso, who will start the race from seventh position.
A fast-finishing Maverick Vinales squeezed in between Quartararo and Marquez with his final attempt, by which time both his colleagues on the front grid were out of action.
Valentino Rossi also had a spill during an eventful session, though he was able to get back to the garage and use his second bike, eventually finishing in ninth position.
Danilo Petrucci came through Q1 to take fifth, behind Franco Morbidelli. Jack Miller claimed sixth on his Pramac Ducati to leave Dovizioso on row three.
1. Fabio Quartararo (Petronas Yamaha): 1:29.719
2. Maverick Vinales (Monster Energy Yamaha): +0.106s
3. Marc Marquez (Repsol Honda): +0.212s
4. Franco Morbidelli (Petronas Yamaha): 0.712s
5. Danilo Petrucci (Ducati): 0.803s
6. Jack Miller (Pramac Racing): 0.878s
7. Andrea Dovizioso (Ducati): 0.973s
8. Joan Mir (Team Suzuki Ecstar): 1.016s
9. Valentino Rossi (Monster Energy Yamaha): 1.022s
10. Alex Rins (Team Suzuki Ecstar): 1.059s
11. Pol Espargaro (KTM): 1.346s
12. Aleix Espargaro (Aprilia Racing Team) 1.539s