Anderson (6-6), who pitched for the Giants in 2020, has held opponents to one run in five of his last six starts.
The Angels scored a run in the third, three in the third and four in the fourth. The Giants had a five-run eighth.
“We swung the bat well and the way the game turned out, we needed it,” Angels manager Ron Washington said. “We did a good job of passing the baton tonight.”
In the third, Taylor Ward scored from first on a bloop double to right by Kevin Pillar after Austin Slater’s throw to second was wide. Moniak, who is on a season-high six-game hit streak, then doubled in two runs to make it 4-0.
Zach Neto drilled a two-run homer to deep left-center field in the fourth. Moniak also tripled and scored in the inning to make it 8-1.
Anderson pitched around five walks, settling down after getting the run support.
“If we’re scoring runs, I need to be not walking guys and giving them the chance to get back in the game,” Anderson said. “So at that point, once we scored eight there, it gave me a chance to go and just be in the (strike) zone.”
Heliot Ramos hit a three-run homer in the Giants’ five-run eighth to cut it to 8-6, but Carlos Estévez finished off the Giants in the ninth for his 11th save.
Giants starter Spencer Howard (0-1) was tagged for four runs in 2 1/3 innings, walking four and giving up seven hits. The Angels knocked around reliever Randy Rodriguez for four more runs.
Howard made his fourth appearance for the Giants as either a starter or featured pitcher as the team deals with several injured starters.
“I felt what the line reflects,” Howard said. “But certainly, you learn much more from the ones that don’t go your way. So I think productive outing, in a way, even though I didn’t give us a very good opportunity to win.”
Wilmer Flores had his 1,000th career hit with a single to lead off the fourth inning, later scoring the Giants’ first run.
Injury updates: Angels right-hander Sam Bachman (shoulder) was reinstated from the injured list and optioned to double-A Rocket City. … Miguel Sanó began a rehabilitation assignment with triple-A Salt Lake on Friday. … Taylor Ward (back) is expected to return to the field Sunday but might continue to be the team’s designated hitter until he’s healthier.
Up next: Right-hander Keaton Winn (3-7, 6.94 ERA) is set to start for the Giants on Saturday against left-hander Patrick Sandoval (2-8, 5.23 ERA).