Deposed world champion Jorge Lorenzo has had successful surgery on his left hand but will miss the MotoGP in Malaysia this week, according to his team.

Lorenzo crashed his Yamaha at the exit to turn 12 on his last lap of the warm-up for Sunday's Australian race, badly damaging fingers on his left hand.

His withdrawal opened the door for Australian Casey Stoner to claim the 2011 world title on his Honda with two races to spare.

Yamaha said Lorenzo underwent surgery in Melbourne on Sunday evening.

"The surgeon was able to save the nerves and tendons of the injured fourth finger. As a result no functionality will be lost in either the finger or the hand," the team said.

"Unfortunately an extended recovery time will be required so Jorge will not race in Sepang for the Malaysian Grand Prix.

"A decision on the Valencia Grand Prix will be made dependent on Jorge's condition after his return to Barcelona."

Lorenzo, the 2010 world champion, was Stoner's closest challenger and his withdrawal meant the Queenslander only had to finish in the top six to wrap up the title.

Stoner opened up a big lead on the first lap and held on despite having to battle treacherous conditions when rain began to fall three laps from the finish.

The Australian slowed right down to ensure he stayed on his bike and eased to a two-second win over Italian pair Marco Simoncelli and Andrea Dovizioso, both on Hondas.