Pierre Gasly won an extraordinary Italian Grand Prix at Monza on Sunday for his maiden Formula One success in his 55th race and the first by a French driver since 1996.
Alpha Tauri's Gasly benefitted from a 25-minute red flag suspension after Charles Leclerc crashed his Ferrari.
Spain's Carlos Sainz was second in a McLaren with Canada's Lance Stroll of Racing Point in third.
Pole sitter Lewis Hamilton was on his way to a comfortable win before a 10-second stop-go penalty pushed the Mercedes world champion to the back of the pack.
The six-time champion eventually ended up in seventh place.
"It was such a crazy race and we capitalised on the red flag," said Gasly who was dropped by the Red Bull team last season.
"I have been through so much in the space of 18 months, to get my first win in Formula 1 I am struggling for words."