Rossi, still nursing an injured finger from his crash at the inaugural Qatar grand prix last week, powered his Yamaha across the line almost four seconds ahead of Italian Max Biaggi's Honda.
Brazilian Alex Barros was third, four places ahead of Rossi's only real challenger for the title, Spain's Sete Gibernau.
Rossi went into the race just 14 points ahead of Gibernau after his crash in Qatar where he had to start from the back of the grid -- a penalty after Honda complained that his team had doctored the track to clean up his starting position.
But Rossi had the last laugh in Sepang, dismounting after his victory, taking a broom that was offered to him and sweeping the ground in front of his bike to laughter and applause.
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