Capuano (6-1) stifled the Diamondbacks on one run, allowing four hits while walking one and striking out five as the National League West-leading Dodgers rolled to their fourth straight win.
Matt Treanor's two-run blast in the second inning staked Los Angeles to a lead it wouldn't relinquish, while James Loney also clouted a two-run homer and Andre Ethier added a solo shot in the victory.
Arizona's Patrick Corbin (2-3) was saddled with the loss after surrendering a pair of runs on six hits over 5 1/3 innings.
Aaron Hill drove in the D-Backs' only run.
Swim Week Miami Beach 2014 [PHOTOS]