NEW YORK — For a rookie who began this month on the bench, Andrew Benintendi is putting up a monster August.

Benintendi rocketed a pair of three-run homers Saturday off Luis Severino and the Boston Red Sox bounced back from a tough loss, roughing up the New York Yankees, 10-5.

“Two beautiful swings,” Red Sox Manager John Farrell said.

A day after blowing a late lead, Boston battered Severino for a career-worst 10 runs. Drew Pomeranz pitched the Red Sox to their ninth win in 10 games and restored their 41/2-game lead over New York.

Boston began bruising the Yankees staff before the first pitch.

Jordan Montgomery was hit in the head by a fly ball while he signed autographs as the Red Sox took batting practice. He bled from a cut on his ear but is still scheduled to pitch Sunday night against Chris Sale in the series finale.

Montgomery was nailed despite standing behind a protective screen in foul ground down the right-field line.

“Just a freak accident,” Montgomery said. “I was behind the net. I mean, there’s a one in a million chance it curves over like that.”

Said Boston catcher Sandy Leon, who hit the ball: “Of course I was watching. I wasn’t trying to hit anybody. It just happened.”

Benintendi, who also homered Friday night, is on a tear. He’s 15 for 31 with four home runs and five steals this month, reaching base 20 times in eight games.

Benintendi went into a slump after the All-Star break, and Farrell sat him for two games.

“A mental break,” Benintendi said.

Benintendi lined a drive off the top of the right-field wall to cap a five-run burst in the third. Third baseman Todd Frazier’s first error in 22 games since being acquired from the Chicago White Sox came on a potential double-play grounder that would have ended the inning without a run scoring.

Benintendi hit a no-doubt drive to right in the fifth for his 16th home run. He matched a career best with six RBI in his third multihomer game this season. He’s also 6 for 11 against Severino lifetime.

According to ESPN Stats & Info, Benintendi is the youngest Red Sox player to drive in six runs against the Yankees since the RBI became an official statistic in 1920.

“I guess that’s cool,” he said.

Benintendi’s performance came in front of his grandfather, who turned 85 this weekend and grew up in Brooklyn as a Yankees fan.

Severino (9-5) was 4-0 with an 0.83 ERA in five starts since the All-Star break. He became the first Yankees pitcher to give up 10 runs at the new Yankee Stadium since it opened in 2009.

Severino was tagged for eight hits and eight earned runs in 41/3 innings.

“Every starter has a bad day. I mean, we’ve seen it for years and years and years,” Yankees Manager Joe Girardi said. “He just didn’t have good stuff. He wasn’t as sharp as he’s been.”

Rafael Devers hit a two-run double that made it 10-2 in the fifth. Mookie Betts had a two-run single for Boston, now 4-7 against New York this season.

Benintendi and the Red Sox solved one of their biggest problems against the Yankees: They started the day just 3 for 64 with runners in scoring position this year, then went 4 for 11.

Pomeranz (12-4) won a career-best fifth straight decision, giving up three runs in 62/3 innings. He also topped his high for wins; he won 11 games for San Diego and Boston last year.

Gary Sanchez hit his 19th homer for the Yankees, a two-run drive in the first. Chase Headley and Jacoby Ellsbury hit consecutive homers in the ninth off Robby Scott, called up by Boston from Triple-A before the game.

NOTES: David Price (elbow) threw in the outfield before the game for the second straight day. Farrell said Price would be checked before Sunday night’s game to see what’s next in his recovery.