Oscar Piastri came from behind to defeat Lando Norris in Formula 1's all-McLaren Spanish Grand Prix pole duel.
Norris was 0.017 seconds up on Piastri after the initial attempts, the pair split by no more than three hundredths in each of the sectors - but while Norris then found 0.06s on his previous best, Piastri strung together a more potent response.
His 1m11.546s lifted him two tenths clear of Norris, the damage done primarily in the second sector.
Max Verstappen found a crucial half-second gain between his opening Q3 lap and his final push to snatch third for Red Bull, having been just fifth after the initial runs. His team-mate Yuki Tsunoda starts last of all in 20th.
Mercedes driver George Russell was the McLarens' biggest rival after those runs instead. Russell lamented on the radio that Mercedes was "too conservative" in not executing something (presumably a slipstream from team-mate Kimi Antonelli) that was worth "two tenths" - and on his second attempt, one that still featured no slipstream from Antonelli, he set the exact same time as Verstappen but set it later, so will thus start fourth.
Lewis Hamilton, in fifth, outqualified Ferrari team-mate Charles Leclerc - who did not do a second Q3 run, having been three tenths up on Hamilton at the halfway point of the session.
That also cost Leclerc sixth, as Antonelli will join Hamilton on row three instead.
Pierre Gasly took eighth for Alpine, followed by Isack Hadjar in the Racing Bulls car and Fernando Alonso in the Aston Martin. Alonso ran 'in the gap' - between most drivers' first and seconds runs - and was audibly delighted with what in that moment looked a very strong lap, but will only start his home race 10th.
Williams, which expected to struggle here, had neither car in Q3 for the first time this season, though Alex Albon was just 0.03s off clawing out a top-10 spot.
"They were dirty! Dirty! Haas - they just knew what they were doing, purposely slow in sector three," he commented after his lap about Ollie Bearman's Haas, pointing perhaps to being disrupted by dirty air.
But Bearman had pulled to the side to let him through out of Turn 12 with minimal fuss - and so the stewards saw nothing worth looking at closer in terms of impeding.
Sauber driver Gabriel Bortoleto was an impressive 12th, followed by Racing Bulls’ Liam Lawson - whose qualifying mini-resurgence spluttered with a so-so final run in Q2 - and Lance Stroll, half a second off Aston Martin team-mate Alonso in the session.
Bearman rounded out the order for Haas, having gone through all fresh sets of softs available to him so only doing a nominal used-tyre lap at the end of Q2.
Nico Hulkenberg was a tenth and a half off rookie Sauber team-mate Bortoleto in Q1 so ended up the fastest of those eliminated, followed by Haas driver Esteban Ocon and home hero Carlos Sainz - who matter-of-factly described his result as "not good" on Williams team radio.
Franco Colapinto sat 11th after running two sets of softs in Q1 ahead of a final push - but his Alpine broke down as he prepared to exit the pits for one more attempt, briefly causing a pit exit bottleneck.
He was thus predictably shuffled down to the back row - but wasn't last, with the second Red Bull of Tsunoda still half a tenth off, having only run two sets of softs himself.
Provisional Spanish GP starting grid
1 Oscar Piastri (McLaren)
2 Lando Norris (McLaren)
3 Max Verstappen (Red Bull)
4 George Russell (Mercedes)
5 Lewis Hamilton (Ferrari)
6 Kimi Antonelli (Mercedes)
7 Charles Leclerc (Ferrari)
8 Pierre Gasly (Alpine)
9 Isack Hadjar (Racing Bulls)
10 Fernando Alonso (Aston Martin)
11 Alex Albon (Williams)
12 Gabriel Bortoleto (Sauber)
13 Liam Lawson (Racing Bulls)
14 Lance Stroll (Aston Martin)
15 Ollie Bearman (Haas)
16 Nico Hulkenberg (Sauber)
17 Esteban Ocon (Haas)
18 Carlos Sainz (Williams)
19 Franco Colapinto (Alpine)
20 Yuki Tsunoda (Red Bull)
