Barcelona - MotoGP world champion Marc Marquez won his home Grand Prix of Catalunya on Sunday after Honda team-mate Jorge Lorenzo took out the Spaniard's main rivals in a mass crash on the second lap.
French rider Fabio Quartararo finished second and 2.660 seconds behind, after starting on pole and dropping to eighth, for the Petronas Yamaha team with Italian Danilo Petrucci third for Ducati.
Marquez's closest rival Andrea Dovizioso and the Yamaha factory pairing of Valentino Rossi and Maverick Vinales went down like skittles after Lorenzo lost control of his Honda at turn 10.
The triple MotoGP champion was late on the brakes as he tried to pass Vinales on the inside, first colliding with Dovizioso before the sliding bikes swept up the two Yamaha riders.
Rossi stayed upright as he went wide onto the runoff before Lorenzo's riderless Honda did for him as well.