With the score tied 3-3 in the seventh inning, the Mets erupted for three runs, triggered when Mike Baxter reached third base on an error and Murphy drove him home with a booming three-bagger into right-center field.
David Wright (3-for-4, two runs scored) followed with a run-scoring single and Buck capped the rally with his second sacrifice fly of the game.
Collin Cowgill added a solo homer for the Mets, who evened their three-game set with the Marlins.
Brandon Lyon (1-0) earned the win with a scoreless top of the eighth.
Marlins reliever Ryan Webb (0-1) was saddled with the loss. Greg Dobbs drove in two runs for Miami.