BALTIMORE—The Orioles finally beat the Boston Red Sox at home behind a strong start by Jorge López, lights-out relief pitching, home runs by Ryan Mountcastle and Trey Mancini and a short but exciting triple by Cedric Mullins.

López, who has had trouble getting through five innings, nearly got through the sixth, limiting the Red Sox to four hits and one run.

Mountcastle hit his third home run of the season in the second, and Mancini hit his seventh in the sixth, and the Orioles scored two more in the eighth for a 4-1 win over the Red Sox before 6,826 at Oriole Park on Monday night.

The Orioles (16-19) had lost six straight to Boston (22-14) at home. They’re just 5-13 at Camden Yards.

Mountcastle’s home run was his third of the season. It came against Martin Pérez. All three of his homers have come against Boston.

Mancini hit his seventh leading off the sixth against Matt Andriese (1-2). The shot to center, the second longest home run of Mancini’s career, traveled 440 feet.

López was pulled after Xander Bogaerts hit a soft liner to center that got past a diving Mullins for a two-out double. Tanner Scott (2-2) struck out Rafael Devers to end the sixth. López struck out five and didn’t walk a batter.

“He went over the hump tonight,” manager Brandon Hyde said. “Probably could have gone longer, but he hasn’t gone that far this year.”

Boston’s only run came in the fourth. J.D. Martinez singled with one out. López hit Bogaerts with a pitch, and both runners moved up on a wild pitch. Martinez scored on Devers’ sacrifice fly to left.

“It wasn’t easy,” López said. “I’m just real excited the way I got my [innings] and give us a chance to keep that ballgame close.”

Travis Lakins and Paul Fry worked perfect innings in the seventh and eighth before César Valdez finished off Boston in the ninth for his eighth save. Oriole relievers pitched a perfect 3 1/3 innings.

In the bottom of the eighth, Mullins hit a popup to short left field. Boston’s defense was in a shift toward the right side and three Red Sox defenders converged on the ball. Bogaerts, the shortstop who was playing on the right side of second base, chased the ball down, juggled it twice, and finally knocked it toward the third base line. Mullins realized the ball might drop and also that no one was covering third. By the time Devers picked it up and threw to catcher Christian Vázquez, Mullins was sliding headfirst into the bag with a triple.

“They should put this on an educational film for all young players on how to get out of the box,” Hyde said. “It was ball hit and eyes up, incredible hustle. He got to third base so fast.”

Austin Hays walked, and Mancini lined a single to center, scoring Mullins.

“I think everything had to happen the way like it did for him to get to third,” Mancini said. “Xander almost had it the first time, almost had it the second time, and then it dropped. Finally, the third time, it bounced. At that point, nobody was covering third. Cedric had already noticed that, and he took off, and he was electric, and got that inning started for us.

“It was a huge inning for us, to put up another couple of runs for us.”

Mancini is batting .252 and has been pleased with his swing since just before the Orioles left for the West Coast on April 29th.

“In this stretch, give or take a couple of games, I’ve felt as good as I ever have,” Mancini said. “I just feel like I’ve lined out like 50 times.

“I’m trying to do what I can up there and focus on my approach and not the result. I feel like that’s produced hard contact pretty consistently. I feel really good about my at-bats lately.”

After Mountcastle struck out, Pedro Severino’s infield single loaded the bases, and Freddy Galvis’ sacrifice fly to right scored Hays to put the Orioles ahead 4-1.

Notes: Galvis’ 10-game hitting streak ended. … Maikel Franco was hitless in three at-bats. He’s in a 3-for-41 slide and his batting average is .205. … The Orioles game with the Minnesota Twins on Memorial Day, May 31st, will be televised nationally on ESPN. Game time is 1:05 pm. … Pitching coach Chris Holt is away from the club for personal matters. Darren Holmes, the assistant pitching coach, who normally works in the bullpen, is subbing. … John Means (4-0, 1.37 ERA) will pitch against the New York Mets’ Marcus Stroman (3-3, 2.10) in the first of a two-game series at Citi Field on Tuesday night at 7:10 pm.