World motorcycle championship leader Jorge Lorenzo won the San Marino MotoGP to extend his lead in the standings while his nearest challenger and fellow Spaniard Dani Pedrosa crashed early in the race in Misano.
Honda rider Pedrosa was involved in a collision with compatriot Hector Barbera and both riders crashed out.
Italy's Valentino Rossi was second, just ahead of Alvaro Bautista. Australian world champion Casey Stoner, third in the overall standings, is out of action after undergoing surgery on his ankle in August.
Lorenzo now has a 38-point lead over Pedrosa, with five races left.