Fabio Quartararo dominated Sunday's Italian MotoGP at a sombre Mugello circuit shaken by the death of Swiss 19-year-old Moto3 rider Jason Dupasquier, who succumbed to injuries sustained in a multi-bike qualifying crash.
"We all know the risks, but its hard to lose one of your own, said Yamaha's French world championship leader, who held up a Swiss flag on the podium in honour of a "friend" whose promising young career was cut short in brutal fashion.
"This one's for Jason. I didn't really know him, he was just a kid. I tried to put it out of my mind but I thought of him every time I went past where it happened," he said of the rider whose death was announced around midday by MotoGP organisers.
"We're deeply saddened to report the loss of Jason Dupasquier," MotoGP said on Twitter.
"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 statement added.
Dupasquier, in his second season in Moto3, fell and was struck by at least one bike before sliding along the track at turn nine during qualifying on Saturday.
Doctors rushed to the scene and after attending to him for 40 minutes on the circuit had him airlifted to hospital.
The rider described as "a leading light of Swiss motorsport" passed away in hospital in Florence after suffering severe brain damage and undergoing chest surgery overnight.
Quartararo said: "It was a strange day, a lot of emotion, every time I passed turn nine I was thinking about Jason.
"It's not a great feeling, you achieve a win but we lose one of our friends."
Quartararo crossed the line with over two and a half seconds of daylight back to Portugal's Miguel Oliveira in second, with reigning world champion Joan Mir completing the podium.
The sixth leg of the season was preceded by a minute's silence for the sport's first fatality since Luis Salom died in practice at the Catalonia Moto2 in Barcelona in 2016.
As the MotoGP roadshow persevered despite the tragic circumstances, it was Quartararo, who had set a new lap record when securing pole on Saturday, who emerged with his third win of the season to tighten his grip on the riders' standings.
He now has a 24-point cushion over Zarco with Francesco Bagnaia, an early faller Sunday, a further two points back in third and Australian Jack Miller, winner of the two races before Mugello, in fourth.
- 'Incompatible with life' -
Miller was among a legion of the sport's leading figures to pay tribute to Dupasquier, the Australian Ducati rider posting on twitter: "Rest In Peace Jason, thinking of his family and team" alongside a red heart.
The Careggi hospital in Florence treating Dupasquier confirmed to AFP that the teenager had suffered brain injuries "incompatible with life".
Motorcycling's governing body the FIM, the teams' IRTA umbrella association, and the sport's commercial rights holder DORNA issued a joint statement on the tragic news.
"Following a serious incident in the Moto3 Qualifying 2 session at the Gran Premio d'Italia, it is with great sadness that we report the passing of Moto3 rider Jason Dupasquier," it read.
His team, Pruestel GP, had already pulled out of Sunday's race, and Tom Luthi, a Swiss Moto2 rider, also withdrew to be close to Dupasquier's family at the hospital.
Japan's Ayumu Sasaki and Spaniard Jeremy Alcoba were the others involved in the horrific accident. Organisers reported that both were "fine".
Dupasquier, whose father Philippe was a former motocross rider, was in his second season in Moto3.
Racing for his German team he finished his rookie Moto3 campaign last year pointless, 28th in the overall standings.
After five races in 2021 he was placed 10th with 27 points.
The FIM joint statement noted: "Dupasquier had made an impressive start to his second season in the lightweight class of Grand Prix racing, consistently scoring points and within the top ten in the standings.
"The FIM, IRTA, MSMA and Dorna Sports pass on our deepest condolences to Dupasquier's family, friends, team and loved ones."