Trailing 6-3 entering their final at-bat, the Phillies took advantage of three walks issued by Brewers closer Francisco Rodriguez (2-5) and banged out three hits to come away with an unexpected victory.
After Philadelphia loaded the bases with one out, Ryan Howard delivered a two-run single, cutting the Phillies' deficit to 6-5. Carlos Ruiz followed with a solid line drive into left field for the tying run.
Rodriguez followed by issuing a walk to Hunter Pence, re-loading the bases, and Wigginton sent a liner to left-fielder Ryan Braun, whose throw home couldn't beat pinch-runner Erik Kratz with the game-winning run.
Howard finished 3-for-5 with a homer and three RBI while Chase Utley also went deep.
Joe Savery (1-2) earned the win as the Phillies took the opener of a three-game set.
Carlos Gomez went 2-for-2 with a three-run homer for the Brewers.