NEW YORK -- Jarred Kelenic smiled while standing along the dugout railing before batting practice at Yankee Stadium on Thursday. It’d just been suggested to the rookie that the ballpark’s short porch in right field could play perfectly for Seattle’s bevy of left-handed bats, especially his.

Kelenic went on to hit a critical, go-ahead homer seven innings later that landed in the first row, a ball that Statcast said would have left just one yard -- this one.

Turns out, it wasn’t the only deep fly of the night that cleared the short wall in right, and the other was far more impactful on the final outcome. Joey Gallo responded to Kelenic’s homer a half-inning later with a three-run shot that also landed in the short porch’s first row, one that proved to be a dagger in a 5-3 Mariners loss.

“I thought as a team, we're seeing the ball well,” Kelenic said. “I thought tonight was a really good game, and it's definitely a tough one to swallow. We thought we had them.”

Paul Sewald was Gallo’s victim on a tough-luck night that dropped the Mariners 3 1/2 games back of the second American League Wild Card and two games behind these Yankees, who are the first team on the outside looking in.

Gallo’s homer hung for 7.3 seconds, traveled just 331 feet and left his bat with a 48-degree launch angle -- by far the highest of the slugger’s career 146 homers and tied for the highest by any Yankees hitter since Statcast began tracking the metric in 2015. With a lift that high, it had an expected batting average of just .200.

But the Mariners came into this series knowing that’s how this yard plays, for and against their benefit.

“Gallo, he's definitely an impressive individual,” Kelenic said. “He's got a lot of power. And when he hit that ball, he scooped it. Off the bat, it sounded great. With that short porch in right, we kind of figured that anything really hit that high is going to go out. It's unfortunate, but he put a good swing on it.”

Sewald was called on to face the top of New York’s lineup and retired DJ LeMahieu and Anthony Rizzo quickly before failing to sit down Aaron Judge and Giancarlo Stanton, each of whom reached two strikes before hitting singles. That set up Gallo, the all-too-familiar face from his days with the Rangers, which ended last week in a Trade Deadline blockbuster to bolster a Yanks lineup that needed a stronger left-handed presence.

“You’ve got to give them credit,” Mariners manager Scott Servais said. “They got the two singles to get guys on base before Gallo hit the popup that went out. And Paul's been just outstanding. He did get behind the count a little bit, but obviously in this ballpark, you want to make pitches and make sure you're executing. That slider that Gallo hit out was probably more middle of the plate than he wanted.”

Thursday’s game showed exactly why the Yanks needed more force from the left side, and it also revealed what the Mariners will be combatting for the rest of this critical four-game series -- and the rest of the season.

These teams won’t face each other again after Sunday, but there will still be eight weeks for the Yankees to create separation in trying to chase down Oakland, which currently holds the final postseason spot, and hold off Seattle, which has now lost four of its first seven on this 10-game road trip. And don’t forget Toronto, which won Thursday to move ahead of the Mariners in the standings and comes to Seattle next weekend.

Yet despite Thursday’s deflating turn, the Mariners ended on a note of making things interesting against Aroldis Chapman, with Kelenic and J.P. Crawford each reaching in impressive left-on-left battles to set up Mitch Haniger, who flied out to the left-field warning track to end the game.

Seattle had 10 hits, set up its bullpen exactly how it planned and rode five strong innings from new acquisition Tyler Anderson, who has been a solid force of length and stability for a rotation that sorely needs it. Anderson gave up just two runs and has now gone at least five frames and with three runs or fewer in each of his past seven starts, with a 3.38 ERA in that stretch.

To that end, the Mariners will wash away Thursday, regroup and return with three more games to trim their deficit against the Bombers in the Bronx.