BOSTON - Los Angeles Angels catcher Chris Iannetta could sense the mood changing in the visitor's dugout at Fenway Park.

A nine-run inning will do that.

Iannetta and Erick Aybar homered as the Angels sent 13 batters to the plate in the fifth, and Albert Pujols also hit a home run on Friday night to lead Los Angeles to a 12-5 victory over the Boston Red Sox.

"Everyone's having a lot more fun after that inning," Iannetta said. "It was a little more loose, a little more laid back."

Mike Trout had a pair of hits — both in the fifth, when the Angels took an 11-3 lead. Boston loaded the bases in the seventh with nobody out and two runs already in, but Jose Alvarez struck out David Oritz and then got an inning-ending double play.

It was the fifth straight scoreless outing for Alvarez, who has lowered his ERA from 10.38 to 2.84 since April 17.

"Jose's really coming on," Angels manager Mike Scioscia said. "You're hoping just to trade an out for a run, an out for a run, and get out of it. And he gets a big strikeout of Ortiz and a double-play ball.

Garrett Richards (4-2) allowed five runs on nine hits and two walks, striking out one in six-plus innings.

Rick Porcello (4-3) allowed seven runs on seven hits and three walks for the Red Sox, striking out four. Matt Barnes relieved him with one out and one on in the fifth, then walked Matt Joyce and gave up Iannetta's homer.

"Nine runs is a tough way to go," Red Sox manager John Farrell said.

Right-fielder Rusney Castillo dropped a fly ball for an error, and one out later Aybar homered to make it 11-3.

It was still 11-3 in the bottom of the seventh, when Boston loaded the bases and scored twice to chase Richards. Alvarez came on to fan Ortiz and get Daniel Nava to hit into a double play.

Boston committed three errors in all.

"There's definite frustration. And that's shared by all in our clubhouse," Farrell said. "We expect more from ourselves."

KICKING IT AROUND

The Red Sox didn't help themselves in the fifth inning, making two errors that led to a pair of unearned runs. Shortstop Xander Bogaerts threw the ball past the third baseman to allow Aybar to score and Trout to take second. Later, after Iannetta's three-run homer, right-fielder Rusney Castillo dropped a high fly popup by Marc Krauss; he scored when Aybar, batting for the second time in the inning, homered.

Bogaerts committed another throwing error in the seventh. The Angels made two errors — a total of five in the game for the teams that had been first and second in the AL in fielding percentage this month.

HE'S IN THERE

Trout scored a run, drove in another, threw a runner out at the plate and singled twice in one inning. But the most impressive thing he did might have been the headfirst slide into third for a stolen base.

The throw from catcher Blake Swihart was there in time, but Trout bent himself out of the way of the tag and reached around the third baseman to get the base. As he slid over the bag, he got his leg onto it before pulling his hand off. Third base umpire John Tumpane called him out, but Trout immediately signalled for manager Scioscia to appeal.

The replay showed he never lost contact with the base.

TRAINER'S ROOM

Angels: Pujols was back in the lineup two days after being hit in the left wrist by a pitch. Although the original fear was he would have to go on the disabled list, tests showed he had only a bruise accompanied by swelling.

Red Sox: LF Hanley Ramirez, who was hit by a pitch in the left hand in the fourth inning, left the game with what the team said was "soreness." Farrell said he had a difficult time gripping the bat. OF Shane Victorino, who was scratched from the lineup on Thursday with a sore left calf, missed another game. 3B Pablo Sandoval got the game off, one night after entering as a pinch hitter. He was hit by a pitch on the side of the left knee on Tuesday.

UP NEXT

Angels: C.J. Wilson (2-2) will pitch the second game of the three-game series against Boston. He is 6-3 with three saves and a 2.63 ERA against the Red Sox in his career.

Red Sox: Steven Wright (1-1) will face the Angels for the first time in his career on Saturday.