France's Pierre Gasly won an astonishing Italian Grand Prix for Italy-based Alpha Tauri in a race packed with suspense and none of the usual top teams on the podium.
McLaren's Spaniard Carlos Sainz finished a close second at Monza after a nail-biting chase to the flag, with Racing Point's Lance Stroll third on a podium of youngsters.
Mercedes's championship leader Lewis Hamilton finished seventh after starting on pole and dropping to last following a 10-second stop/go penalty for entering the pit lane under a red light while leading.
Despite the setback, the six-times world champion retained his 47-point lead at the top -- now over team mate Valtteri Bottas, who was fifth, after Red Bull's Max Verstappen retired.
Hamilton has 164 points after eight races to Bottas's 117 and Verstappen's 110.
It was the first time since 2013, when Kimi Raikkonen triumphed with Lotus in Australia, that a team other than Mercedes, Ferrari or Red Bull had won a race.
"It's unbelievable," gasped Gasly, who was dropped by Red Bull's main team last year but has come on in strides in the strangest of seasons disrupted by COVID-19 and without spectators. "It was such a crazy race and we capitalised on it.
"I've been through so much in 18 months, I struggle to realise this."
The victory was a first in F1 for Gasly, the first for a French driver since Olivier Panis in 1996 and the second for the former Toro Rosso team whose only other win was also at Monza with Sebastian Vettel in 2008.
"I was so close but yet so far," said Sainz, who had also dreamed of taking his first win before joining Ferrari next year. "I needed one more lap."
The race had to be stopped at the halfway mark after Ferrari's Charles Leclerc crashed heavily into the tyre wall at Parabolica.
Leclerc's team mate Sebastian Vettel had already retired with brake failure and the chances of hearing the Italian anthem on the podium had appeared to be nil up to that point.
The standing restart from the grid, and Hamilton's penalty that left the Briton having to make up a 30-second deficit, set up a thrilling 17-car sprint and a glimpse of what a reverse-grid race might look like.
-Reuters