Max Verstappen just denied Williams' George Russell an incredible pole position in a dramatic rain-hit Belgian GP qualifying session which saw early pacesetter Lando Norris crash out heavily.
Lewis Hamilton, the championship leader, will start from third with Russell - strongly tipped to join his countryman at Mercedes next year - astonishingly finishing between the big two F1 title rivals on the grid.
Russell's Williams' team are eighth out of 10 teams in the world championship and last claimed a front-row, also in the wet, at Monza in 2017.
Norris himself had been threatening a run at a first career pole, topping Q1 and Q2, but crashed heavily in increasing rain at the start of the pole shootout at the fast Eau Rouge corner.
With his McLaren getting away from him in the middle of the uphill right-hander, Norris spun into a big impact with the outside barrier, before the car came back across the circuit.
Norris was able to get out of the crashed car unaided and told the team over the radio he was OK. He was taken to the circuit's medical centre for mandatory check-ups and has now gone to hospital for a precautionary X-ray on his elbow.
After a lengthy delay to the session, the Q3 shootout resumed in slightly improved conditions with Hamilton setting the initial pace before Russell threatened to pull off the biggest qualifying shock for years by outpacing the world champion on his final lap.
But Verstappen was going fractionally faster behind and pipped Russell to an astonishing P1 by three tenths of a second.
"I thought we would have been doing a good job to get out of Q1 after yesterday, now we're standing on the front row," said Russell about his barely-believable result.
With Hamilton shuffled back to third, McLaren's Daniel Ricciardo took a season-best fourth ahead of Aston Martin's Sebastian Vettel in fifth and AlphaTauri's Pierre Gasly with sixth.
Valtteri Bottas was only eighth in the second Mercedes - and that will become an even more problematic 13th on Sunday's race grid owing to the Finn's five-place grid penalty for causing the first corner carnage at the last race in Hungary.
Belgian GP Qualifying: Top 10
1) Max Verstappen, Red Bull
2) George Russell, Williams
3) Lewis Hamilton, Mercedes
4) Daniel Ricciardo, McLaren
5) Sebastian Vettel, Aston Martin
6) Pierre Gasly, AlphaTauri
7) Sergio Perez, Red Bull
8) Valtteri Bottas, Mercedes*
9) Esteban Ocon, Alpine
10) Lando Norris, McLaren
*5-place grid penalty
Russell tames the rain in astonishing front-row run
In a sport where relative car performance is so often a determining factor for a driver, wet weather can act as a relative leveller - and that was certainly the case for Russell on Saturday.
The 23-year-old has already established himself as one of the grid's best qualifiers but it was still only recently - at the Austrian and British Grand Prixs in July - that he was able to make Q3 in a Williams for a first time.
He made it a hat-trick at Spa but what was eighth on intermediate tyres in Q2 suddenly transformed into run at pole when the drivers when it truly mattered in Q3.
"The car was feeling great and I was confident," said Russell.
"I was in a fortunate position where I had nothing to lose in Q3. Absolutely buzzing."
On a fresh set of tyres for his final attempt, Russell dismantled Hamilton's initial provisional pole time in the lap's first sector alone and, although his seven-time world champion countryman also improved his lap, the Williams was still faster by 0.013s.
Verstappen ultimately was quicker than both, but Russell's front-row was by then guaranteed.
"Tomorrow's the important one," he noted. "If the lead is there for the taking we'll go for it!"