The Ferrari driver had it all to do in the last part of qualifying after spinning at the penultimate corner during his banker lap in Q3 but then the points leader stunned on his second attempt.
A run to 1m18.750s marked comfortably the fastest lap of the weekend as he seized his 13th F1 pole position by three tenths over his ground-effect title rival Verstappen.
The defending champion, who held provisional pole after his first Q3 effort, was forced to abort his final flying lap after his Red Bull endured yet more unreliability and died at Turn 3.
Comfortable Q2 pacesetter Verstappen had not long delivered a crushing run through the final sector to extract a four tenth advantage on his first flying lap in the final part of qualifying to post a 1m19.073s.
That threw him to the top of the timing screens as he ran a mighty 0.35s ahead of provisional pacesetter Carlos Sainz, while Sergio Perez clocked third ahead of the Mercedes pair.
Leclerc was the major name missing from the top of the times after he threw away his first Q3 lap with a Turn 14 spin despite setting five session-best mini-sectors over the lap.
The rear axle of the Ferrari rotated into the left-handed part of the tight chicane when, like at Imola, he grabbed too much kerb. He then locked all four tyres bringing the car to a stop.
Leclerc was equipped with a fresh set of soft tyres and headed out comparatively early for the qualifying climax, leaving his garage with three and a half minutes left to play.
But he stitched together the fastest second and third sector to romp to pole.
After the power cut, Verstappen was eventually able to restart his car, and his first go proved enough to complete the front row ahead of Sainz, who fell a tenth adrift with his 1m19.166s.
George Russell led the renewed effort from Mercedes with fourth place as he nipped ahead of Perez, while Lewis Hamilton ran to sixth after his first Q3 lap was hurt by oversteer out of the final corner.
Valtteri Bottas snared seventh for Alfa Romeo ahead of Kevin Magnussen, while Daniel Ricciardo was resigned to ninth after McLaren elected not to send him out for a second Q3 charge.
Mick Schumacher's Haas, meanwhile, completed the top 10.
Lando Norris failed to progress into the top 10 by 0.035s when the stewards deleted his final flying lap in the 15-minute session for marginally exceeding track limits at Turn 12.
The McLaren driver, who also clipped the Turn 14 bollard, had just prevented Schumacher from squeezing into Q3 before his lap was binned and he was relegated.
Esteban Ocon aborted his second effort in Q2 to tether himself to 12th, while Yuki Tsunoda nipped ahead of AlphaTauri team-mate Pierre Gasly.
The French racer had struggled with Turn 5 understeer on his final run, having sat out almost all of FP3 owing to a fire igniting on his installation lap.
Alfa Romeo rookie Guanyu Zhou rounded out the top 15.
World champions Sebastian Vettel and Fernando Alonso were the major scalps to be claimed in the first part of qualifying as they were shuffled into the bottom five places.
Alpine driver Alonso, preparing for his home race, was forced to back out of his final flying lap thanks in part to early traffic from Norris, however the stewards decided not to intervene. That left Alonso prey as the customary flurry of improved times landed late on.
The better laps from Gasly and Ricciardo secured their progression and subsequently dropped Vettel and Alonso to a final 16th and 17th on the leaderboard.
Vettel, having missed the Q2 cut-off by 0.07s, did at least manage to out-qualify team-mate Lance Stroll as the Canadian guided the heavily scrutinised and updated AMR22 to just 18th.
Alex Albon pipped Williams stablemate Nicholas Latifi to round out the final row of the grid.
F1 Spanish Grand Prix Q3 results
| Cla | Driver | Chassis | Engine | Time | Gap |
|---|---|---|---|---|---|
| 1 |  Charles Leclerc | Ferrari | Ferrari | 1'18.750 | |
| 2 |  Max Verstappen | Red Bull | Red Bull | 1'19.073 | 0.323 |
| 3 |  Carlos Sainz | Ferrari | Ferrari | 1'19.166 | 0.416 |
| 4 |  George Russell | Mercedes | Mercedes | 1'19.393 | 0.643 |
| 5 |  Sergio Perez | Red Bull | Red Bull | 1'19.420 | 0.670 |
| 6 | Lewis Hamilton | Mercedes | Mercedes | 1'19.512 | 0.762 |
| 7 |  Valtteri Bottas | Alfa Romeo | Ferrari | 1'19.608 | 0.858 |
| 8 |  Kevin Magnussen | Haas | Ferrari | 1'19.682 | 0.932 |
| 9 |  Daniel Ricciardo | McLaren | Mercedes | 1'20.297 | 1.547 |
| 10 |  Mick Schumacher | Haas | Ferrari | 1'20.368 | 1.618 |
| View full results | |||||
