World champion Fabio Quartararo crashed out in first lap mayhem at the Aragon MotoGP on Sunday.
The Frenchman's Yamaha clipped returning six-time title winner Marc Marquez's Honda.
Quartararo slithered across the track as his Aragon curse continued at the Motorland circuit where he has never made the podium.
Seconds later Honda's Japanese rider Takaaki Nakagami also hit the deck, after contact again with Marquez, whose dream return had turned into a first lap nightmare.
Marquez, competing for the first time in 112 days after further surgery on the right arm he injured in 2020, was forced to retire with damage to his bike.
"It was really unlucky," Marquez told motoGP.com.
"On turn three I had a moment, when Fabio was really close and there was contact.
"I felt something strange in turn five, turn 7 was ok, but coming out of it the bike started to lock and go on the left side. I had a piece of, Fabio's bike attached to mine."
Quartararo's misfortune severely dents his hopes of defending the title with closest challenger Francesco Bagnaia only 30 points adrift after winning the last five races.