The Italian, who started in pole position and also won Saturday’s sprint race, headed an all-Ducati podium, with Spain’s Jorge Martin finishing second and Frenchman Johann Zarco coming third.
Bagnaia now has 131 points after Sunday’s win, 21 more than second-placed Marco Bezzecchi of the VR46 Ducati satellite team set up by Valentino Rossi.
Bezzecchi came eighth at Mugello on Sunday.
“It was a perfect weekend,” Bagnaia said following his win.
“I didn’t expect a race like that.
“I was sure that the rear tyre would have been more constant, but by the last few laps it was in bits.
“But I’m very happy with the enormous job that has been done.
“Now let’s focus on next week’s race at the Sachsenring.
“But before that let’s enjoy this moment, one of the best of my life”.
Earlier, on Saturday, Bagnaia won the sprint race in rainy conditions.
He headed an all-Ducati podium, with Bezzecchi second and Team Gresini’s Jorge Martin third.
It was Bagnaia’s third sprint win of the season, while he has made the podium in five of the six sprints.
Rain threatened to wreak havoc early on but the sun peeked out from behind the dark clouds at Mugello, though the riders still had to deal with wind and drizzle on sections of the track.
“It was a bit scary in the end with rain in sector two and three,” Bagnaia said on Saturday.
“I just tried to not leave any chance for him (Bezzecchi) to overtake. I really enjoyed today.”
The Ducati factory team rider came in ahead of Marc Marquez (Honda) and the Spaniard’s brother Alex (Ducati team Gresini).
Ducati team manager Davide Tardozzi asked the race stewards to look at whether Marquez’s sought to disrupt Bagnaia on his flying lap, by coming out on the pits as the latter was about to hit the first corner and then riding on his rear-wheel.
The move prompted Bagnaia to direct some pointed hand gestures at Marc Marquez.
ANSA
