Trumbo connected for a long shot into the Angels' left-field bullpen against Phil Coke (0-2) while leading off the bottom of the 13th for the Angels.
The clout made a winner of Jerome Williams (1-0), who had fired three innings of scoreless relief.
Albert Pujols drove in a pair of runs for Los Angeles, which outscored Detroit 22-4 in the series.
Prince Fielder launched a two-run homer for the Tigers, who dropped a fourth straight overall.
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