The 2018 Red Sox lost Alex Cora’s first career game as a manager.

The 2025 Red Sox lost his 999th at Fenway Park on Thursday afternoon, falling to the Seattle Mariners 4-3 to drop the series.

It was a career day for Red Sox starter Garrett Crochet, though not in ways he’d like. The left-hander needed 110 pitches, a new high, to get through five innings, and he issued five walks for the first time.

Crochet’s command was off early, and he became the fifth consecutive Sox starter to give up at least one run in the first inning. Dylan Moore, the American League Player of the Week, led off with a single, advanced on a balk, and he and Randy Arozarena, who’d drawn his first of three walks, scored on Mitch Garver’s RBI double.

Another two runs in the second proved all the Mariners needed, but the Red Sox pitching staff did everything they could to keep their team in the game. After a 1-2-3 third, they had at least one baserunner in every inning until Luis Guerrero, recalled from Triple-A for his season debut, set them down in order in the eighth and ninth.

Crochet stranded two runners apiece in the fourth and fifth, getting a swinging strikeout to end each frame. Greg Weissert, too, worked around a pair of baserunners in the sixth, and Liam Hendriks got a bases-loaded strikeout to finish the seventh. All told, the Mariners collected nine hits and eight walks, but went 3 for 13 with runners in scoring position and left 12 men on base.

“I put the team in a bad spot, and I had to get us out of it. What with the innings I left on the table, the bullpen did a really good job,” Crochet said of the way he finished his later innings and being allowed to finish the fifth despite a career-high pitch count. “It’s nice to get out of the jam. I put myself there, though, so just blaming myself.”

As for how to get away from what he called “pitching passively,” Crochet said throwing first-pitch strikes is key, but explained how important the mental aspect is for him.

“It became something where I was trying to pitch instead of just throw,” he said. “Once I started getting back to my roots and just being a power-pitcher later in the game, the walks were still there but I was at least able to get guys out.”

Pitching, he explained, is “hitting your spots and painting,” which he said isn’t who he is.

“For the most part I do a lot of my work in the heart of the zone,” Crochet said, “and I think that I was getting away from that because I was having success (painting), so it was kind of like, what’s the next thing that I could work on, and just always trying to work on something as opposed to, you get to a point where you just got to continue what you’re doing.”

For Crochet, that’s the four-seam.

“That’s what got me to the big leagues, and that’s what helped me make a name for myself last year. No reason to get away from that, even if they know what’s coming,” Crochet said. “I was talking to Tanner (Houck) about that on the bench. Those last couple innings when it was mano a mano, that’s kind of when I’m at my best, still missing bats with it even though it was in fastball counts for the most part, throwing three, four five in a row, doesn’t matter. Just kind of got to get back to that mentality.”

Of the Red Sox’s 27 games, 17 have been decided by no more than three runs, including 10 of their last 15. Several losses can be at least partially attributed to their struggle to hit with men on base — they entered Thursday with 196 runners left, the most in the AL and tied for second in MLB — but this time, they barely had any runners to strand. Boston collected four hits and two walks, and struck out 12 times.

“He battled, he gave us a chance,” third baseman Alex Bregman said of Crochet. “We didn’t do enough offensively today, to be honest with you.”

Bregman was the offense, getting Boston on the board with towering Green Monster homer in the first, plating the team’s second run with an RBI single in the third, and drawing a walk, all against Mariners right-hander Bryan Woo.

“He’s the player I expected, so I’m not surprised,” Cora said of Bregman.

The Boston batters were otherwise befuddled. They entered the contest leading the American League in home batting average and on-base percentage, and second in OPS and runs scored, but Jarren Duran’s leadoff double in the third was the sole non-Bregman hit off the Seattle starter, and their only other baserunner against him was Triston Casas, hit with a pitch in the second.

“Yeah, we didn’t do enough off him today,” Bregman said of Woo. “We didn’t square the ball up enough. … Sometimes in the game you run into a guy who’s really tough and you tip your hat to him.”

It was more of the same against Collin Snider, who breezed through a 1-2-3 seventh.

Carlos Narváez’s solo homer to lead off the eighth was Boston’s first hit since the third inning, and their last of the contest. His homer off Gabe Speier clanged off the Pesky Pole and brought the Red Sox within one, but it couldn’t rewrite a game that seemed written in stone since the start.

After Narváez’s homer, his teammates went down in order. And facing Andrés Muñoz in the ninth, Casas drew a two-out walk, only to watch Kristian Campbell strike out to complete a golden sombrero and cement the loss.

The Red Sox are 14-13, including 4-5 in one-run games. They’re 4-4 in series play, including 2-2 at home. Nearly one month into the season, the most consistent thing about them is inconsistency. Postgame, the reviews were mixed.

“I feel like there are times when we click and there are times (like) today when we’re facing a really good pitcher on the mound and the offense is doing everything they can to get some runs on the board,” Crochet said. “I mean, the game was the first two innings that I pitched. That was really what lost us the game today.”

“I feel really good,” Bregman said. “I feel like we’re only going to improve as the season goes on. I think we got a long way to go, obviously, but I think we’re in a good spot. We gotta get better in all three phases, we know that, and we will.”

“I mean, we’re OK,” Cora assessed. “Almost playing .500. We can be better, we can be worse.”

After going 4-3 during this homestand, the Red Sox fly to Cleveland for the weekend, then have Monday off before a three-game series in Toronto.