PITTSBURGH — Chris Bassitt became a hero for the Mets on Wednesday by steering the rotation back on its expected course with quality and length.

If not his best performance of the season, it might have been Bassitt’s biggest given the team’s recent play. Bassitt fired seven strong innings in carrying the Mets to a 5-1 victory over the Pirates in Game 1 of a split doubleheader at PNC Park.

The Mets entered the day in a flat-footed tie with Braves atop the NL East before snapping a three-game losing streak — in which Max Scherzer, Carlos Carrasco and Taijuan Walker failed to pitch beyond the fifth inning.

“I’m sure the world was going crazy, but we’re fine,” Bassitt said.

A night earlier the Mets’ lead on the Braves (which was seven games as recently as Aug. 10) disappeared completely. But Bassitt said Atlanta’s surge hasn’t put any additional pressure on the Mets.

“It’s just win today and that’s it,” Bassitt said. “I understand the standings and how well the Braves are playing, but we can only control what we can. Do everything smart and worry about us and that’s it.”

Added Eduardo Escobar: “The Braves are a good team and you have to give a team like that credit. It doesn’t matter that we haven’t had the results, it’s that they have also played well.”

Early homers from Tyler Naquin and Escobar accounted for most of the Mets’ scoring, leaving Bassitt with a comfortable lead to protect against these last-place Pirates.

The right-hander allowed one earned run on five hits with 10 strikeouts and one walk, departing after 101 pitches. Seth Lugo followed with two scoreless innings in relief.

“I mixed everything well,” Bassitt said. “I kind of prepared for a lot of lefties and got what we were wanting to have, so we were prepared for them.”

Naquin — starting in right field a day after Starling Marte was drilled by a pitch on the right hand and departed the game — blasted a three-run homer in the fourth inning against Bryse Wilson that gave the Mets a 4-0 lead. The homer was Naquin’s fourth since arriving from the Reds on July 30.

Daniel Vogelbach singled and Mark Canha was hit by a pitch to start the rally. After Naquin homered, Escobar followed with another, extending the Mets’ lead to 5-0. The back-to-back homers were a fifth-time occurrence for the Mets this season.

Escobar’s homer was his third in five games, continuing a surge from the switch hitter since he returned from an oblique strain that placed him on the injured list.

“I haven’t done anything much different from what I have done from the beginning of the year,” Escobar said. “I think the biggest difference of what I have done is swinging at pitches inside the strike zone, so I think when you swing at good pitches you have good results.”

Pete Alonso’s double from the No. 2 hole in the batting order (he was moved from cleanup with Marte absent) helped the Mets take a 1-0 lead in the first inning on Jeff McNeil’s sacrifice fly. Brandon Nimmo led off the game with a single and scored the run.

Bassitt didn’t dent until the sixth, when he surrendered an RBI single to Tyler Heineman that pulled the Pirates within 5-1. Greg Allen doubled leading off the inning and Rodolfo Castro later walked, but Bassitt escaped further damage by retiring Jack Suwinski to leave two runners stranded.

Though the Pirates announced 8,717 as attendance, there might not have been more than 2,000 fans in the ballpark for Game 1 — a makeup from a Monday postponement.

“In this environment you have got to challenge yourself to pitch with that intensity, the first game of a doubleheader,” manager Buck Showalter said. “That is typical Chris, we have come to expect that from him.”