Melbourne sent a statement of intent to the rest of the National Rugby League by bouncing their second top-four rival in the space of a week.
The victims this time were the Sydney Roosters, in a bruising 30-6 encounter in Melbourne.
The premiers ran a first-half steamroller over the Roosters, then extended their advantage in trying second-half conditions as heavy rain-swept Olympic Park.
In the night's other game, St George Illawarra pulled off a 24-20 comeback win in Brisbane, denting the Broncos' attempts to paint themselves as serious threats to Melbourne and Manly for the premiership.
The Dragons' fourth straight win over Brisbane at Suncorp Stadium also ruined champion five-eighth Darren Lockyer's milestone 298th first grade appearance, which eclipsed the previous best held by winger Michael Hancock.