Ohtani went deep into the seats in right-centre field in the seventh inning off Giants left-hander Taylor Rogers in his ninth game of the season, ending the longest season-opening homer drought of his major league career. Ohtani finished 2-for-4 with two runs.
The Dodgers have scored at least five runs in all nine games this season to extend their franchise-record and move closer to the New York Yankees' record of 13 games in 1932.
Tyler Glasnow (2-0) won for the second time in three starts and Miguel Rojas added a home run as the Dodgers finished 6-1 on their first homestand of the season.
Red Sox 1, A's 0
Nick Pivetta teamed with four relievers for an eight-hit shutout as Boston completed a three-game sweep at Oakland.
Enmanuel Valdez lifted a sacrifice fly in the fourth inning for the game's only run, allowing Pivetta (1-1) to earn the win in a pitchers' duel with Oakland's Ross Stripling (0-2).
Pivetta limited the A's to five hits in five innings, and Kenley Jansen escaped a ninth-inning jam for his second save. Stripling allowed eight hits and one run in seven innings.
Astros 8, Blue Jays 0
Yordan Alvarez homered twice and finished with four hits and three RBIs as Houston beat visiting Toronto in the rubber match of a three-game set.
Jose Altuve and Jeremy Pena also went deep for Houston, while Cristian Javier (1-0) gave up one hit in five innings. The Astros outhit the Blue Jays 15-1, though Houston pitchers issued seven walks.
Chris Bassitt (0-2) allowed four runs on nine hits in 4 1/3 innings for the Blue Jays.
Guardians 8, Mariners 0
Jose Ramirez hit two doubles and had two RBIs and Logan Allen pitched 6 2/3 scoreless innings as Cleveland routed host Seattle.
Leadoff hitter Steven Kwan went 3-for-5 and scored three times for the Guardians, who took two of three games in the series. Allen (2-0) allowed four hits, walked three and struck out six.
Mariners starter George Kirby (1-1) lasted just 3 2/3 innings and was tagged for eight runs on 10 hits.
Angels 10, Marlins 2
Miguel Sano reached base four times, Patrick Sandoval rebounded from a forgettable Opening Day start and Los Angeles completed a three-game sweep of host Miami.
It was the Angels' fourth win in a row, while the Marlins are now 0-7, the longest losing streak to start a season in franchise history.
AJ Puk (0-2) threw four innings, allowing four runs (two earned) on five hits and three walks, striking out five for Miami.
