The Frenchman, who drives for Alpha Tauri, took the chequered flag at Monza just 0.4 seconds clear of McLaren’s Carlos Sainz with Racing Point’s Lance Stroll completing an unpredictable podium.
Lewis Hamilton finished only seventh after he was forced to serve a 10-second stop-and-go penalty for stopping for tyres when the pit lane was closed.
"OH MY GOD!! WHAT DID WE JUST DO?! DID WE WIN THE ****** RACE?! WE DID IT AGAIN!!!" - @PierreGASLY, 2020#ItalianGP 🇮🇹 #F1 pic.twitter.com/45BZqX15pw
— Formula 1 (@F1) September 6, 2020
Hamilton, who until that point appeared on course to cruise to his 90th career win, described the decision as “bull****”.
The best race of what has been a turgid season took a dramatic twist when the Safety Car was deployed on lap 20 with Kevin Magnussen’s Haas parked up in a dangerous position.
Hamilton had established a 11-second lead over the McLaren duo of Sainz and Lando Norris before diving into the pits too soon and facing the wrath of the stewards.
Stroll stayed out, moving him to second, while an early stop from Gasly promoted him to third. The Frenchman had started 10th on the grid.
With Magnussen’s car removed, the race restarted on lap 24 but a little more than a minute later, Charles Leclerc crashed out at one of the fastest corners on the calendar.
The Ferrari driver was midway through the Parabolica when he veered into the barriers at speeds approaching 180mph.
Leclerc was winded in the huge accident but managed to remove himself from the cockpit.
“Are you OK?” asked the Ferrari pit wall. A breathless Leclerc responded: “Yes, it was a big crash.”
The red flags were deployed, with the cars pulling into the pit lane and Hamilton appearing to head to the stewards’ office to protest his penalty.
A 27-minute delay ensued with Stroll, who had not stopped, allowed to take on fresh rubber.
How things stand as we await the restart!#ItalianGP 🇮🇹 #F1 pic.twitter.com/I8Tou4D2Xl
— Formula 1 (@F1) September 6, 2020
But a poor getaway after the red-flag period blew the Canadian’s chances. Indeed, it was Gasly, the 24-year-old, who got the best start moving into second behind Hamilton.
The world champion then stopped to serve his penalty with Gasly assuming the lead.
Sainz hustled Gasly to the flag, with McLaren bidding to win their first race since 2012, but it was the French driver who prevailed to claim his maiden grand prix win.
Gasly was in tears as he crossed the line, screaming in delight following a memorable win.
British driver Norris finished fourth ahead of Valtteri Bottas, only fifth following a poor start. Daniel Ricciardo was sixth for Renault ahead of Hamilton, who passed eight cars and claimed the fastest lap of the race following his penalty.
His nearest title challenger Max Verstappen retired with a technical problem, while Sebastian Vettel also failed to reach the end following a brake failure.
