BOSTON — The Mets were ahead by one run, but still needed 17 outs from the bullpen as play resumed Saturday in their game against the Red Sox that had been suspended Friday night.

It sounded like a dicey proposition for a team that has weathered much turmoil from its relievers, particularly in the middle innings of games in which starters haven’t provided length.

Yet the Mets figured it out, with near optimal results from the five pitchers they deployed in finishing a 5-4 victory at Fenway Park.

The Mets won for the fourth time in five games, but were still five games below .500 as they prepared for the regularly scheduled game against the Red Sox, which had been shifted to Saturday night.

Grant Hartwig, David Peterson, Dominic Leone, Brooks Raley and David Robertson combined for those 4 ²/₃ innings, allowing only one run.

And the Mets squeezed out one more run, enough to supplement the pair of two-run homers Brandon Nimmo and Daniel Vogelbach hit on Friday night before heavy rain stopped the game in the fourth inning and forced a suspension after nearly a two-hour delay.

“It’s one thing to map out potentially what you would like to do,” manager Buck Showalter said, referring to the bullpen. “It’s another thing to get the other team to cooperate with you … people did their job and it allowed us to stay in turn to where they are best equipped to get outs.”

The rookie Hartwig had scuffled in his last two appearances after a strong start to his Mets career, but rebounded Saturday with two scoreless innings.

He took the ball as the game resumed in the bottom of the fourth with one out and departed with one out in the sixth.

“I just did my job — I was going until they told me I couldn’t,” Hartwig said. “That’s all I was planning to do and my job was to get it to the guys at the end of the game.”

Hartwig said the extended duty — pitching in parts of three innings — was a challenge he knew he could handle.

“Most guys that have been in the bullpen have been starters most of their lives,” Hartwig said. “That third up-down really doesn’t make a huge difference for me. But going in with a mindset of going for length definitely changes the approach a little bit more. You kind of want to be more on attack with your pitches and keep that pitch count low.”

Brett Baty’s infield single in the sixth inning extended the Mets’ lead to 5-3.

Pete Alonso doubled off the Green Monster to start the inning and reached third on a wild pitch before Baty’s grounder, which was gloved in the shortstop hole by Yu Chang, brought in the run.

Peterson escaped trouble in the sixth.

Rafael Devers’ single off second baseman Luis Guillorme’s chest put runners on the corners.

Guillorme departed the game with a right calf injury following the play.

After Devers’ hit, the lefty retired Adam Duvall on a lineout to short and struck out Alex Verdugo to end the threat.

Mark Canha misplayed Triston Casas’ double into a triple leading off the seventh.

The ball rolled between Canha’s legs as he pursued it in the right-field corner. Chang’s sacrifice fly pulled the Red Sox within 5-4.

Leone recorded three outs in the inning after Peterson was removed following Casas’ triple.

Kodai Senga had allowed three earned runs on three hits and a walk over 3 ¹/₃ innings before the game was suspended on Friday.

That snapped a stretch of three straight starts in which the right-hander had allowed fewer than three earned runs.

Jarren Duran’s stolen base and advancement to third on Francisco Alvarez’s throwing error helped the Red Sox take a 1-0 lead in the first inning on Justin Turner’s RBI groundout.

Chang’s two-run double in the second inning put the Mets in a 3-0 hole, but Senga retired the final five batters he faced.

Nimmo’s 14th homer of the season, a two-run shot in the third, began the Mets’ comeback against Kutter Crawford.

In the fourth, Vogelbach’s two-run homer gave the Mets a 4-3 lead.