Ohtani, 32, launched his 20th home run of the season off pitcher Michael Lorenzen in the bottom of the first inning.
The homer brings his season batting average up to .297 and OPS to .956. Ohtani now has 56 RBI on the year and was the first player to be named to this year's National League All-Star team, making it six-straight seasons of being an All-Star.
He's also tossing a jaw-dropping 1.79 earned run average with 95 strikeouts through 85.2 innings as a starting pitcher this season (8-2 record, 14 starts).
The four-time MVP who led the National League in runs the past two seasons continues his reign as the best player in baseball. Ohtani now has at least 20 home runs in six straight seasons, and in seven of his nine years in the league.
His 300 home run record now stands far and away from any other Japanese player, as Hideki Matsui sits in second with 175. The two, along with the legend Ichiro Suzuki, are the only Japanese players ever to hit at least 100 home runs in MLB.