Mayberry tied the game with a solo homer in the 10th inning and then brought the contest to an abrupt end with a walk-off grand slam in the bottom of the 11th.
Mayberry didn't get into the game until the seventh inning when he was inserted as a pinch hitter. He finished 2-for-3 with five RBI and two runs scored. He tied the game 3-3 with a leadoff homer in the 10th and then connected again in the 11th on a 1-1 fastball from Edgar Olmos (0-1) to give the Phillies their third consecutive win.
Erik Kratz had a game-tying double in the seventh for the Phils. Michael Stutes (1-0) got the win as the last of six Philadelphia pitchers to work the game.
The Marlins had their three-game winning streak come to a close. Casey Kotchman and Rob Brantley each drove in a run.