Batting first, the Port Boys struggled for runs with skipper Chris Wood scoring 47, while Chris Davenport managed 29.
The Dragons quick bowlers were superb up front, restricting the hosts to 157, with returning paceman Simon Mackin taking 3-36.
Matt Hanna was also impressive taking four scalps. Chris Chellew then bowled the Fremantle side to victory with 3-28.
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READ NOWAlex Hepburn was the only Dragon to pass 30, as the team folded for 149.