BOSTON — Mike Trout can cross Fenway Park off his home run to-do list.

Trout hit a home run at Fenway for the first time, and the Los Angeles Angels snapped an eight-game losing streak Saturday with a 12-4 rout of the Boston Red Sox.

With his 428-foot drive over the Green Monster in the sixth inning, Trout has homered in every American League ballpark. He had played 21 games in Boston without connecting.

“I didn’t think about it,” Trout said. “I think I got reminded about it every time I’ve come here.”

After two at-bats against Red Sox starter Rick Porcello in which he struck out and grounded out, Trout came up again, and Porcello missed on a fastball that went straight over the middle of the plate.

Trout made him pay for it.

“I hit it good,” Trout said. “He pitched me tough my first two at-bats. I was looking for a pitch to hit and I got one.”

Trout was replaced in the seventh after being hit in the shoulder by a pitch earlier in the game. Trout said he felt fine.

Justin Upton hit a three-run homer in the first inning.

The Angels scored seven times in a sloppy seventh inning by Boston, which issued two walks, hit two batters and gave up four singles. The Red Sox also had an error and a passed ball.

The loss denied Boston its first three-game winning streak since it won three straight against the Yankees in late July. It’s also yet another head-scratching setback for the defending World Series champions, who looked to be turning a corner following an eight-game losing streak.

“We’ll keep working, we’ll keep going,” Manager Alex Cora said. “There were some positives, but obviously at the end we need results as a team.”

Taylor Cole (2-3) pitched 1 2/3 innings of scoreless relief to pick up the win.

Porcello (10-9) took the loss, giving up both home runs. He lasted five innings, allowing five earned runs on five hits, walking one and striking out four.

“Sixth inning, I throw three pitches, give up two runs. It’s tough; I’ve got to be better,” Porcello said.

Porcello retired 14 straight batters after Upton’s homer, but for the first time in several starts didn’t get run support.

Porcello entered the night having won five of his previous six starts despite allowing 26 earned runs in 341/3 innings. But he also had benefited from a major-league-leading 7.3 runs per start by Boston’s offense.

The Red Sox left 11 runners on base after outscoring the Angels 19-4 in the first two games of the series.

NOTES: Red Sox first baseman/outfielder Steve Pearce (low back strain) hit in the cage and ran lightly in the outfield. He said he can do everything but run sprints after being set back by a partially torn ACL. “In this game, you have to be able to run and you need to be able to burst, and that’s what I’m having trouble doing right now,” he said. Pearce said the ACL injury won’t require surgery.