Leclerc delivers emotional first home-town win in Monaco
Three time world champion Max Verstappen scraped in sixth after Sergio Perez crashed out, the Mexican's Red Bull ripped apart, in a first-lap pile-up.
Leclerc in contrast had a Sunday afternoon drive he will remember for the rest of his life.
The 26-year-old, who had not claimed a Monaco podium in his five previous attempts, became the first Monegasque to win at home since the world championship started in 1950.
After climbing from his car, he jumped into the arms of his team after finally translating pole position into victory on his home streets at the third attempt.
Fighting back tears, he said: "No words can explain it. It’s such a difficult race. I think that twice starting on pole position and we couldn't get it makes it even better.
"It means a lot. It is the race that made me dream of becoming a Formula One driver.
"Already the emotions were coming, 15 laps from the end, I was thinking of my dad a lot more than what I thought while driving.
"He has given everything for me to be here. It was our dream for me to race here and to win so it is unbelievable."
His triumph ended his run of failing to win from his previous 12 pole position starts and was received with popular acclaim by a big crowd packed into the famous Mediterranean harbour on a sunlit afternoon.
Leclerc came home 7.152 seconds ahead of nearest rival Oscar Piastri of McLaren with Carlos Sainz taking third in the second Ferrari ahead of Lando Norris in the second McLaren.
George Russell was fifth for Mercedes ahead of Verstappen and seven-time champion Lewis Hamilton in the second Mercedes.
In a race that was re-started after three accidents on the opening lap Yuki Tsunoda of RB finished eighth ahead of Williams’ Alex Albon and Pierre Gasly of Alpine.
High speed chess
On a perfect Riviera afternoon Leclerc made a clean start to pull clear while behind him Piastri and Sainz went into Ste Devote side by side and collided.
Before Sainz could recover, the race was red-flagged when Perez and the two Haas cars tangled at the back of the field.
Perez spun and clipped the barriers before he hit Nico Hulkenberg and then Kevin Magnussen at an estimated 240 kph on the climb towards Massenet. "Unnecessary," said a furious Hulkenberg. Magnussen faced a possible race ban if he was penalised but escaped blame.
In another opening lap incident, the two Alpines collided when Esteban Ocon attempted to dive inside Gasly at Portier but succeeded only in creating an airborne drama. Ocon faced a 10-second penalty, to be applied as a five-place grid drop in Canada, and the fury of his team.
All the drivers were unscathed in the mechanical carnage, but the damage to a barrier at Beau Rivage required lengthy repairs before a re-start.
Sainz was restored to third on the grid and this time made an uneventful start behind Leclerc and Piastri.
More than ever, the race was about tyre management as Leclerc controlled a steady pace at the front to the frustration of Russell, in fifth on mediums, ahead of Verstappen and Hamilton. The top four were all on hards.
"At this stage, George, we gain nothing from driving faster," Mercedes told Russell while Verstappen’s Red Bull engineer Gianpiero Lambiase warned "he’s just giving them a free pit-stop gap eventually."
This cat-and-mouse form of high-speed chess, by pit-wall boffins and their drivers, reduced the spectacle to procession, the top four separated by less than a second, and Russell nine seconds back in fifth, with Verstappen and Hamilton, all on mediums.
By lap 26, of the 78, even the drivers were suffering ennui. "This is really boring,” said Verstappen. “I should have brought my pillow."
For the leading teams, it was about calculating risks, gaps and tyre-wear with Leclerc in charge and the rest tempted by stopping to gain a potential ‘under-cut’ and a fresh-tyre charge.
On lap 39, Ferrari requested Leclerc to slow and reduce the gap from Norris, in fourth, to Russell. “What is the scope in that?” asked Leclerc before obeying.
The pack had to follow suit and closed up, but despite pit-stops by Hamilton and Verstappen, the order remained unchanged at the flag.
After at last getting his hands on the jewel in the Formula One calendar Leclerc moved to within 31 points of Verstappen in the increasingly more open title race ahead of the Canadian Grand Prix in a fortnight's time.