As he battled his emotions, Antonelli, who only turned 20 two weeks ago, admitted on team radio that “it feels like a dream”.
His win was delivered from the most distant starting position since John Watson raced to victory for McLaren at the 1983 United States Grand Prix West in Long Beach from 22nd on the grid.
More pointedly, victory over teammate George Russell opens up a 66-point lead in the title race.
“It’s a dream come true,” he said.
“What an incredible day. I couldn’t do this without my team, my family and everyone who supports me.”
He resisted the temptation, however, to talk about becoming the first Italian world champion since Alberto Ascari in 1953.
“There’s still a few races to go, so we will try to keep our heads down. But now, yes, we are going to enjoy today.
“I did not expect this. Unbelievable. Unbelievable. I am so happy. I could not have imagined to be here today, but we managed to pull it off and I am really, really happy.”
Antonelli did have one scare in the race, four laps from the end when he was trying to overtake Russell and found himself in the gravel.
“It was quite scary because the tarmac was breaking up, but I still thought I could do the corner.
“I went straight. I was thinking like maybe I lost my chance, but luckily we had the pace and I could bring it home.”
Starting Sunday’s race from the back of the grid due to penalties after taking a new power unit, he said he had felt capable of winning after going from 19th to 12th in the opening laps.
Then Charles Leclerc crashed his Ferrari to bring a red-flag stoppage and a re-start.
“After the second re-start, I was up there and I knew I could have had a shot for the win. So definitely I believed in it, especially when I was behind George,” he said.
“But it was difficult to break away with it all being so strong. At the end we pitted, he stayed out and he struggled with his tyres at the end so with fresher tyres we could increase the pace and get the win.” (AFP)