BOSTON -- The weather was dreary, and so was the end result for the Mariners.

Playing on a rainy Fenway Park Sunday afternoon, the Mariners were swept in the three-game series with an 11-2 loss to the Red Sox.

• Box score

While soaked fans watched covered in ponchos, the Mariners seemed to be affected by the damp conditions, too.

“Both teams had to play in miserable conditions out there today,” manager Scott Servais said. “Obviously, not a good series for us. Rough road trip.”

Shed Long slipped on the grass in right field chasing a popup in the first inning, allowing Xander Bogaerts to score on the Michael Chavis hit. One batter later, Rafael Devers scored from third base on a passed ball by Omar Narváez.

“I just tried to stop, and [my] feet came [out] from under me,” Long said. “The whole field was wet. … It’s on your mind, but at the end of the day, I’ve got to make the play.”

In the second, Jay Bruce committed a fielding error for dropping a Mookie Betts fly ball, which scored Andrew Benintendi. The Mariners found themselves trailing, 4-1, after two innings.

Starting pitcher Marco Gonzales allowed four hits, four runs (two earned, including a home run by J.D. Martinez) while striking out three off 95 pitches in four innings. Twenty-eight-year-old Parker Markel made his Major League debut in relief, giving up three hits, two runs and a walk in his first official inning. In total, five Mariners threw 189 pitches, while three Red Sox threw 133.

“There’s a certain degree where it gets to you a little bit and you want to push through and kind of warrior up,” Gonzales said. “I thought the mound was OK. I thought it was a little muddy and sticky at times, but again, I don’t think that’s an excuse for the amount of pitches.”

The Mariners attempted to make in-game adjustments to adapt to the weather conditions. Gonzales noted that he checked his cleats throughout the game and made sure he had a grip on the ball.

“I think just taking the game a second slower in those situations kind of helps,” Gonzales said.

Long also took note on defense to make sure he didn’t slip a second time.

“The next fly ball that I went out there on the grass, I knew I had to feel my feet under me,” Long said. “Don’t get too out of control, because I was running full speed, trying to stop on a dime and that’s not going to happen.”

The Mariners allowed a total of 34 runs to the Red Sox in the series while producing just eight. After getting off to an historic 13-2 start to the season, they dropped to 20-23. Seattle heads west to start a six-game homestand against the Rangers and A’s.

“We’ve got to get back home and kind of regroup and go from there,” Servais said.