With the score tied 3-3, Gordon led off the ninth by smacking a pitch from Jonathan Papelbon (0-2) into the right-center field gap, legging it out for a triple.
The next batter, Elian Herrera, then shot a grounder through a drawn-in infield to drive home Gordon with the decisive run.
Gordon also delivered a run-scoring single in the second inning while Bobby Abreu added two hits and an RBI for the Dodgers, who won for only the second time in eight contests and maintained a three-game lead over second-place San Francisco in the National League West.
Ronald Belisario (1-0) earned the victory with a scoreless eighth and Kenley Jansen picked up his seventh for Los Angeles, which took the opener of a four-game series at Citizens Bank Park.
Placido Polanco belted a two-run homer for the Phillies, losers of three straight.