The MotoGP field gathered for a minute’s silence before the 23-lap race to commemorate 19-year-old Moto3 racer Jason Dupasquier, who died of injuries in qualifying on Saturday.
The drama of the race began before the lights went out, when Avintia rookie Enea Bastianini Johann Zarco ran into the rear while warming up his brakes on the warm-up lap.
As a result, Zarco suffered some damage to the tail unit while Bastianini had to miss the race, but the start was not delayed.
The race management will investigate the incident after the race.
Bagnaia took the lead at the start to San Donato, but Poleman Quartararo was not swallowed up in the field thanks to Yamaha’s new front holeshot device.
The Ducati’s performance meant Quartararo couldn’t do much to keep Bagnaia within range on the 1.1km first straight as they started on lap two.
Behind them, Honda’s Marc Marquez met with KTM’s Brad Binder and crashed in the Poggiosecco right-hander – Petronas SRT’s Franco Morbidelli fell back to the bottom as he was forced to deviate from the track in order to evade.
The drama continued a few corners later when the leading Bagnaia crashed in Arrabbiata 2 after running a bit offline, giving Quartararo clean air to take advantage of the cornering speed of his Yamaha.
Quartararo had to deal with Pramacs Johann Zarco in laps three and four, with the Yamaha rider making a decisive move in Poggiosecco.
From then on, Quartararo steadily expanded his lead at a rapid pace, the Frenchman was three seconds ahead of the rest to get his third win of the 2021 season.
Zarco stayed in second place until lap 16 when KTM’s Miguel Oliveira got through while the Pramac rider was soon threatened by the Suzukis behind.
Alex Rins and Joan Mir fought tightly for fifth place in the early stages, but the strong late pace put them on the podium in the closing stages.
World champion Mir whizzed past Zarco in the Palagio left turn and took third place on lap 17, while Rins further demoted the French on the following tour in the Saveli left turn.
But after falling from strong positions in the last three races, Rins’ miserable run continued when he slipped on the last corner on lap 19.
On the final lap Mir closed the revived Oliveira’s KTM but couldn’t do anything to overtake the Portuguese.
Oliveira was downgraded from second to third because he had slightly exceeded the track limits at the exit of Borgo San Lorenzo directly in turn 5 on the last lap.
Oliveira’s runner-up, however, was reinstated after it was believed that Mir had also crossed the course limit at the same point on the final lap
Zarco held fourth place, 1.3 seconds ahead of Binder, while Jack Miller’s only remaining factory Ducati team was only sixth.
Aleix Espargaro finished seventh on the Aprilia ahead of a battered Maverick Vinales, who had to recover from 16th place after a bad start.
Danilo Petrucci finished ninth on the Tec h3 KTM ahead of Valentino Rossi on the Petronas SRT Yamaha, while Iker Lecuona (Tech 3) defeated Hondas Pol Espargaro in 11th.
The final points went to Pramac’s deputy Michele Pirro, Alex Marquez from LCR and Lorenzo Savadori from Aprilia, while Morbidelli took 16th place ahead of Luca Marini from Avintia.
Takaaki Nakagami was a late crash on the second LCR Honda.
Quartararo’s victory now lifts him 24 points ahead of Zarco in the overall standings, Bagnaia is now 26 behind him after his fall.