Dukes started the scoring with a two-run, first-inning single.
Orr had two hits, one a two-run homer in the third inning.
Cristian Guzman had three hits and one RBI.
Despite two rain delays, the winner was starter John Lannan (9-11).
Cody Ross led Florida with two hits and one RBI.
Jorge Cantu hit a run-scoring single, giving him six RBI in the last two games.
Hanley Ramirez had three hits and Cameron Maybin two for the Marlins, who had won four of five.
Volstad (9-12) was the losing pitcher.