Sunday's race is live on the BBC Sport website and 5 live Sports Extra at 13:10 BST
Valtteri Bottas led Lewis Hamilton to a Mercedes one-two in Azerbaijan Grand Prix qualifying as Ferrari's challenge crumbled.
Charles Leclerc had looked favourite but Ferrari's new star crashed in second qualifying and will start ninth.
"I am stupid," Leclerc said on the radio before saying on social media: "No excuses. I've been useless. I will push to have a better tomorrow."
His team-mate Sebastian Vettel was third, 0.302 seconds off the pace.
Hamilton had been fastest on the first runs in final qualifying but appeared to be compromised by being too close behind Bottas at the start of his final lap, and then lost 0.3secs in the first sector.
He made up time on the rest of the lap but ended up just 0.059secs behind the Finn.
Leclerc has outperformed his illustrious team-mate, but this is his first big mistakeFast Ferrari mess it up again
It was a grave disappointment for Ferrari, for whom Leclerc had been the form man from the start of the weekend.
Leclerc again looked quick in first qualifying, although Red Bull's Pierre Gasly pipped him to fastest time with a later lap, and the 21-year-old was quick on his first lap on medium tyres in second qualifying, with Ferrari preferring them for the start of the race, only to smash into the wall at Turn Eight on his second lap.
Leclerc went in too fast to the tight left-hander leading into Baku's section around the historic medieval castle, locked a wheel and understeered into the barriers.
He was clearly dejected as he climbed out of the car and looked to the skies in dismay.
Turn 8 proved to be a nightmare for several drivers
"I am very disappointed in myself," Leclerc said. "I have been very strong all weekend but it is a mistake I shouldn't have done. I will focus on that for a few hours and understand what I could have done to not have that mistake but I will push to come back and have a good race tomorrow."
Leclerc's pace on his first lap was strong enough to get him through into the top 10 shoot-out but he could not take part as a result of the extensive damage to his car.
But because Alfa Romeo's Antonio Giovinazzi has a 10-place grid penalty, Leclerc will be promoted ahead of him and start ninth. From there, on a divergent strategy starting on the mediums, he is likely to feature in the fight for a podium by the end of the race.
Red Bull's Max Verstappen was fourth, 0.574secs off the pace, ahead of Racing Point's Sergio Perez, Toro Rosso's Daniil Kvyat and McLaren's Lando Norris, who continued the impressive start to his debut season with eighth place.
At the back, George Russell impressed to out-qualify team-mate Robert Kubica despite missing all his Friday running after his car was damaged when he ran over a loose man-hole cover.
Russell was 0.393secs quicker than Kubica, who ended his session in the wall at Turn Eight, misjudging his entry, hitting the inside wall and cannoning into the barrier on the outside.
Kubica was the first to come to grief around the medieval castleWhat they said
Bottas said: "I am really happy. Ferrari have been really strong. Charles was out by a mistake and as a team we did everything to take an advantage."
Hamilton said: "It has been so close all weekend. Ferrari have looked incredibly quick. Valtteri did an exceptional job in qualifying. It is a massively great result for us. We didn't have an upgrade and there others did and for us to lock out the front row due to circumstances I am really grateful for it."
Vettel admitted Ferrari were disappointed with the result.
He said: "I don't know if they stole it. I think they were a bit quicker than us today. It was difficult to find the ring balance of pushing with the out lap and playing with two and trying to get something. I had a good lap but I had no tow.
"Happy to get sort of the maximum out of it but from a team point of view we were expecting to have a better session."
Bottas and Hamilton celebrate another Mercedes front-row lockout - the fourth in four racesPerfect view: The famous Flame Towers in BakuKubica's Williams team-mate George Russell was the first driver to run into trouble during Friday's practice session, in which his car was badly damaged by a loose drain cover before the recovery truck it was sitting on drove into a bridge. Safety fears also arose after two marshals were run over during the Formula 2 support race
