Shohei Ohtani homered on the first pitch Wednesday night and tossed five scoreless innings to lead the visiting Los Angeles Dodgers past the San Diego Padres 4-0.

Ohtani (4-2) permitted three hits and walked two while striking out four in an 88-pitch effort. Four relievers finished up the five-hitter, enabling Los Angeles to win the first series of the year between the National League West rivals.

San Diego starter Randy Vasquez (5-2) absorbed the loss, yielding six hits and three runs in 4 1/3 innings with three walks and no strikeouts. The right-hander was on the ropes from the moment he toed the rubber.

Ohtani clouted a high fastball over the wall in deep right-center, just over leaping center fielder Jackson Merrill, for his eighth homer of the year. Adding literal injury to insult, Merrill left the game after four innings with an apparent back injury sustained during his unsuccessful effort.

Teoscar Hernandez made it 2-0 in the second when he lofted a sacrifice fly that scored Max Muncy, who doubled to lead off the inning and reached third via Will Smith's single.

The Dodgers added a run the fifth when Kyle Tucker stroked a one-out RBI single off reliever Wandy Peralta to plate Ohtani.

San Diego didn't manage a baserunner off Ohtani until Fernando Tatis Jr. coaxed a leadoff walk in the fourth. A single by Gavin Sheets put runners at first and second before Ohtani induced a pop-up and flyout to end the threat.

The Padres' best chance to score happened in the fifth. Bryce Johnson singled and reached third on Nick Castellanos' single. Freddy Fermin walked with one out to load the bases, but Ohtani got Tatis to ground into an inning-ending double play.

In the eighth, San Diego nudged runners to first and third with one out on singles from Ramon Laureano and Tatis, plus a throwing error. But Kyle Hurt induced a 6-4-3 double play ball from Miguel Andujar to quash the rally.

Hernandez capped the scoring in the ninth by walloping a leadoff homer into the second deck in left, his sixth of the year.