BOSTON -- The Mariners’ four-game series in Boston ended on a familiar note as they watched Franchy Cordero launch a walk-off grand slam over the bullpen in the 10th inning, for an 8-4 Red Sox win and series sweep on Sunday afternoon.

For the Mariners, it was another ball they were unable to keep inside of Fenway Park, something that happened 10 times in the series, with five of those coming off the bat of Trevor Story.

“Story got hot,” said Seattle manager Scott Servais as to why his team allowed so many home runs. “He had five? Take him out of the mix and we’re probably OK. That happens.”

Sure, Story did connect for three long balls in the series opener on Thursday, then a grand slam on Friday night before sending a solo shot out Sunday, but the aggressive Red Sox lineup was tough to contain on all fronts for the Mariners, with 23 of the 33 runs scored against them coming by way of the home run.

Rafael Devers hit two in the series and Jackie Bradley Jr., Christian Arroyo and Cordero all contributed one each, with Sunday’s game-winner coming off reliever Andrés Muñoz on an 0-2 slider with one out.

“[Muñoz] made a mistake and paid dearly for it,” Servais said.

More frustrating for the club on Sunday was how it battled back twice -- which included a ninth-inning home run from Eugenio Suárez that sent the game to extra innings -- and how it was able to get a strong seven innings out of starter Logan Gilbert, who struck out four and allowed three runs.

“I thought it was pretty good,” said Gilbert of his pitch command. “I felt like I didn’t have most of my stuff early on. I was trying to find it along the way. We were able to get creative and make it work and go seven.”

Be it a pitcher missing with one of his offerings or simply not having his “stuff” on the night, the Mariners have worn it on their sleeve, with Robbie Ray admitting the grand slam he allowed to Story on Friday was “a matter of one pitch” and Chris Flexen, who allowed two home runs on Saturday, owning that he simply made “mistakes and [the Red Sox] hit every single one of them.”

With the 10 home runs allowed over the past four games, the Mariners run their team total to 56 home runs allowed, the most in the Major Leagues by four.

“We’ve had some adversity early in the season,” said Servais. “More than we really bargained for. But that’s just the way it goes. You’ve got to figure out a way to fight through it.”

The Mariners were able to push a run across in the top half of the 10th inning, but Boston tied it in the bottom and then loaded the bases to set up the walk-off home run.

The loss ended a 10-game road trip in which the team went 3-7, losing six of it's last seven. It was the second time the Mariners were swept this season (the first was at Houston from May 2-4).

“It’s been a rough trip for us, rough go of it here in the last few weeks,” said Servais. “But our guys come with a good attitude every day, and they really did compete their tail off today. Unfortunately, it didn’t get to go our way at the end.”

Seattle returns home on Monday to open a three-game series versus Oakland at T-Mobile Park.