The Sharks, who already have wrapped up a spot in the playoffs, increased their division lead to seven points over the Ducks. San Jose has won three straight and 14 out of 15.
Anaheim missed out on a chance to clinch a playoff berth.
Roenick scored on the power play 72 seconds into the third period. Roenick bested Jonas Hiller, who made 41 saves to keep the Ducks in the game.
San Jose's Evgeni Nabokov was called upon to make just 12 saves.
The Ducks had won six in a row in San Jose.
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