Ohtani hit his 100th career home run, Ward hit a grand slam and the Angels salvaged a split by beating the Oakland Athletics 9-1 in the nightcap Saturday.
The A's won the opener 4-3 when Luis Barrera overcame a couple of earlier blunders by hitting a walk-off, three-run shot for his first career home run.
"Give our guys credit," Angels manager Joe Maddon said of the response in Game 2. "Not an easy loss to endure. We did it, I thought really well."
The Angels took little time to rebound in the second game with Ward hitting his second slam of the season in a five-run second inning against Adam Oller (0-3).
In the fifth inning Ohtani followed Mike Trout's RBI double with his milestone homer to make it 8-1.
"One hundred is a big number," Ohtani said through an interpreter. "I'm proud of it. But it's early in the season."
That made Ohtani the third Japanese-born player with at least 100 homers in the majors, trailing only Hideki Matsui with 175 and Ichiro Suzuki with 117. Ohtani also joined Babe Ruth as the only players with at least 100 home runs and at least 250 strikeouts as a pitcher.
"He does it every day," Maddon said. "It's not surprising anymore. I don't want to say expecting it, but we're expecting it. That's just who he is right now. He's going to keep adding on to that. You're going to hear more names, more milestones. He's a baseball player. He loves to play."
That was more than enough support for Michael Lorenzen (4-2), who allowed one run and five hits in seven innings.
Oller, called up from the minors as the 27th man for the doubleheader, allowed eight runs in five innings and has a 12.27 ERA in four starts this season.