The at-bats leading up to the sixth inning for Gunnar Henderson were promising, displaying the plate discipline that has made him such a standout player despite being the youngest in baseball. But with a crack that split the late evening chatter at Fenway Park, Henderson’s resounding swing broke him out of the first slump he has experienced in the majors.

Henderson clobbered a home run to straightaway center field Monday night, a two-run bomb left his bat at 111.1 mph — the hardest hit ball of his career. The blast was part of the offensive onslaught before and after a 100-minute rain delay from the Orioles in a 14-8 win against the Boston Red Sox, starting the final road trip of the season on a positive note.

Baltimore dropped two winnable games against the Houston Astros over the weekend, missing a chance to gain ground in the wild-card race, even though it came against the best club in the American League.

Now, with a win to begin the series in Boston, the Seattle Mariners aren’t fully in the clear. The Orioles moved within 3 1/2 games of the Mariners for the final American League wild-card spot with nine games remaining.

“We’re confident,” starting pitcher Jordan Lyles said. “We didn’t love how the Houston series finished up, the second half of those four games. But we know how talented we are. We can get on a run. I strongly believe that a lot of the guys in [the clubhouse] believe that, also. It’s up to us. If we go on a run, we go on a run.”

To do so, the Orioles (80-73) will need to carry over some of the success Monday into the remainder of the series in Boston before facing the New York Yankees and Toronto Blue Jays to end the year.

Henderson had entered his sixth-inning at-bat on an 0-for-16 skid, but his plate appearances had been strong; he walked three times earlier in the game before coming to the plate and wowing in the sixth. The rookie sent his fourth homer 428 feet off right-hander Kaleb Ort.

The earlier plate appearances showed Henderson’s plate discipline, his willingness to seek the right pitch rather than get antsy at the plate in the midst of a minor slump. And then when he saw that four-seamer in a sweet spot, he didn’t miss.

“I felt like I was able to take some close pitches and get myself into advantage counts,” Henderson said. “It felt like a good swing, but it felt like even when I was going through it, I had some hard-hit balls that went right to them. You go through that.”

The noise from Henderson’s swing echoed around a quiet and nearly empty Fenway Park.

“That was as loud as we’ve had all year,” manager Brandon Hyde said.

Baltimore feasted on Boston’s pitching staff, even with a lengthy rain delay following the second inning. That barrage backed up a solid outing from right-hander Spenser Watkins, who entered in relief of Lyles.

The rain delay shortened Lyles’ outing to two innings, during which Hyde made an unusual mound visit to a starting pitcher. Lyles’ four-seam fastball velocity was 2.1 mph slower than average this season, according to Statcast. He still limited the damage, allowing a solo homer to J.D. Martinez before Kiké Hernández drove in a second run.

Hyde said he wanted to check to make sure Lyles was OK after throwing his first complete game last week in 10 years. The answer was yes. And while the velocity was down for Lyles, the 31-year-old chalked it up to a small sample size.

“I would love to say I can ramp it up after the first couple innings,” Lyles said. “I’m hard in with some sinkers [to the right-handed batters.] There’s not a lot of four-seams down and away. I don’t know. It was only two innings worth.”

The cushion for Lyles and the rest of Baltimore’s staff was large, however, with Mullins’ leadoff homer setting up a four-run second inning off right-hander Connor Seabold. And after the delay, a triple from Kyle Stowers off the Green Monster — the second three-bagger of the game, following Cedric Mullins’ two-run triple — drove in another run in the third.

That cushion shrunk in the fourth, when Boston plated three runs off Watkins to cut the deficit to one. Yet the bats quickly made up the distance again, with Anthony Santander clubbing his 30th and 31st homers of the season, joining Eddie Murray and Ken Singleton as the only Orioles switch hitters to reach that number.

“It means a lot, honestly,” Santander said through team interpreter Brandon Quinones. “I want to thank God for giving me the opportunity to be healthy all through this season, and I think that’s been the biggest key for me to be able to reach that mark this year.”

As Watkins and right-hander Logan Gillaspie maneuvered the Red Sox lineup down the stretch, Baltimore tacked on offensively, weathering the six runs off the relievers. It was a positive start to a road series, keeping the door to the postseason cracked open.

But to enter it, the Orioles will need more nights like Monday.

“If we can maintain the same energy we had today and keep it moving forward as we continue to fight, I think it’ll be great,” Santander said. “We feel good about our chances.”

Around the horn

In order to get a fresh arm in the bullpen, Baltimore optioned left-hander Keegan Akin to Triple-A Norfolk and recalled Gillaspie. The Orioles said the decision wasn’t based on Akin’s performances, although he has an 8.13 ERA in six appearances this month.
Infielder Ramón Urías said the spasms he has dealt with between his right shoulder and neck felt better Monday and that he should be available off the bench. He has been in and out of the lineup after he first experienced the spasms last week, reaching for a towel in the shower to trigger the painful reaction. “I talked to the manager and I said I’ll play with pain or without pain,” Urías said.
Infielder Terrin Vavra is dealing with a sore hamstring and wasn’t in the lineup Monday. He exited Sunday’s game after playing six innings.
Pitchers Beau Sulser and catcher Cam Gallagher joined the taxi squad. Gallagher, a recent waiver claim from the San Diego Padres, grew up in Lancaster, Pennsylvania. He said he was a fan of the Orioles and Philadelphia Phillies, and “I grew up watching Cal Ripken [Jr.] play,” he said.

ORIOLES@RED SOX

Tuesday, 7:10 p.m.

TV: MASN2

Radio: 97.9 FM, 101.5 FM, 1090 AM

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