George Russell was left with an "incredible feeling" after he upset the odds to claim his first pole position for Mercedes at the Hungarian Grand Prix as Red Bull endured a dismal day.
Carlos Sainz, seeming more comfortable in the Ferrari with every race, appeared destined for pole from his flying lap at the Hungaroring.
However, Russell, having complained of a lack of grip throughout the practice sessions, came almost from nowhere to put together a remarkable final lap and take top spot with a time of one minute and 17.377 seconds.
He prevented a Ferrari one-two after the Red Bulls had been removed completely from the equation. Sergio Perez failed to make it out of Q2, alleging he was blocked by the Haas of Kevin Magnussen, and Max Verstappen then complained of a loss of power in the top-10 shoot-out. Championship leader Verstappen will start 10th, ahead of Perez in 11th.
Ferrari are still in a tremendous position to take advantage of Red Bull's woes, with Sainz set to start second ahead of Charles Leclerc in third.
"I'm over the moon. Absolutely buzzing," said Russell, whose team-mate Lewis Hamilton could only manage seventh amid an issue with his DRS.
"The lap time kept on coming. I came across the line and saw we went P1 and that was an incredible feeling."
Asked if it means Mercedes are back, Russell replied: "I don't know to be honest, we need to look and understand where that came from, there's a few ideas we had.
"There's no points for qualifying. Generally we had good race pace, but the Ferraris looked very fast on Friday, but we are going to be absolutely going for it [tomorrow], but either way that was a pretty special day no doubt."
Leclerc and Sainz appeared relaxed despite missing out on locking out the front row.
Leclerc will have the McLaren of Lando Norris for company on the second row, with the Alpines of Esteban Ocon and Fernando Alonso behind them in fifth and sixth.
"Mostly we are focusing on ourselves," Ferrari's Leclerc said when asked about Red Bull's problems. "I've been struggling massively with the tyres. I struggled to put a lap together.
"I'm pretty sure we've got the pace in the car to come back at the front. I'm pretty sure we can come back tomorrow."
Sainz looked much more assured than his team-mate but echoed Leclerc's sentiments after losing critical time in the final part of his final flying lap.
"Definitely feeling better and better every race and every qualifying session," Sainz said. "I felt like I had the pace to do the pole position, it went away from us.
"We have the [race] pace; the start and the tyre management will play a key role. The Mercedes pace is a bit of an unknown."
PROVISIONAL CLASSIFICATION
1. George Russell (Mercedes) 1:17.377
2. Carlos Sainz (Ferrari) +0.044
3. Charles Leclerc (Ferrari) +0.190
4. Lando Norris (McLaren) +0.392
5. Esteban Ocon (Alpine) +0.641
6. Fernando Alonso (Alpine) +0.701
7. Lewis Hamilton (Mercedes) +0.765
8. Valtteri Bottas (Alfa Romeo) +0.780
9. Daniel Ricciardo (McLaren) +1.002
10. Max Verstappen (Red Bull) +1.446