Charles Leclerc's pole position for Sunday's Monaco Grand Prix hangs in the balance – as Lewis Hamilton pointed the finger at Mercedes after he qualified only seventh.
Ferrari's Leclerc became the first Monegasque to secure pole in the principality since Louis Chiron 85 years ago, but his 110mph crash with just 16 seconds of qualifying remaining could see him sent down the grid.
Leclerc's front-right tyre brushed the Armco on the entry to the swimming pool chicane, destabilising his Ferrari, and sending him over the kerb and into the barrier on the opposing side of the track.
The crash ended not only Leclerc's session, but all those gearing up for one final shot at pole in Monte Carlo.
A furious Max Verstappen sent the airwaves blue as he was forced to settle for second, despite being faster than Leclerc's pole lap at the time of the Ferrari driver's accident. Valtteri Bottas took third with his Mercedes team-mate Hamilton down in seventh.
Leclerc's wounded Ferrari will now be assessed to see if the gearbox is salvable. If it is replaced, Leclerc will incur a five-place grid drop, promoting Verstappen to pole, and relegating him from hero to zero with Ferrari chairman John Elkann watching on in Monte Carlo.
"I have mixed feelings because I don't know where I am starting," said Leclerc in the moments after claiming his eighth pole and Ferrari's first since the 2019 Mexican Grand Prix.
"My head is all over the place. I hope the car is not damaged too much so we have to start further back.
"I was on the last lap and trying to do more in the final sector and I hit the barrier on the inside and I went straight into the wall."
Carlos Sainz finished fourth in the other Ferrari ahead of Lando Norris in his McLaren.
Hamilton leads Verstappen by 14 points in the standings, but he was anonymous throughout qualifying and faces a tall order on Sunday with overtaking notoriously difficult.
Hamilton finished third in practice, but accused his team of taking backward steps with the set-up of his Mercedes which left him unable to generate enough heat into his tyres.
"A lot of the work gets done on Saturday, so I'd definitely say we're out of contention for the win," said Hamilton.
"There will be some tough discussions that I'll have with my engineers tonight, or maybe after the weekend, because there are things that should have been done but have not been done.
"I cannot say too much because I don't want to be critical of the team but behind closed doors, I will be. We've got to work harder.
"Final practice on Saturday morning was a disaster and that is because of the work we did over the last day. We went in completely the wrong direction and completely missed the ball.
"We made some changes to move the car into a better place and the car was worse than ever so we really lost our way from Thursday.
"I have my frustrations. I know there is nothing I can do now but I was feeling hopeful on Thursday that we could fight in the top three."
Mick Schumacher did not take part in qualifying after he crashed out of final practice.
The rookie, and son of seven-time world champion Michael, lost control of his Haas on the exit of Casino Square and slammed into the barriers in the closing minutes.
Schumacher, 22, sustained severe damage to the left-hand side of his car, and Haas were unable to repair his machine in time.
The young German, who will start Sunday's race at the back of the grid, appeared in tears as he was consoled by his team.