
Dupasquier, 19, was struck by another bike after falling and slid along the track at the Mugello Circuit. He was flown to a Florence hospital.
“Despite the best efforts of circuit medical staff and all those subsequently attending to the Swiss rider… Dupasquier has sadly succumbed to his injuries,” MotoGP said.
“On behalf of the entire MotoGP family, we send our love to his team, his family and loved ones You will be sorely missed, Jason. Ride in peace.”
The MotoGP grid held a minute’s silence before Sunday’s Grand Prix.
France’s Fabio Quartararo, who won the race, dedicated his victory to Dupasquier, while he and the other two riders to finish on the podium – Portugal’s Miguel Oliveira and Spain’s Joan Mir – held up the Swiss flag as a tribute.
Prustel GP, his team, posted: “We’re devastated, and at this time all of our thoughts are with Jason’s family. You’ll be sorely missed and never forgotten.”