In his mind, manager Terry Collins had it all mapped out. If Mets starter Robert Gsellman could simply finish the sixth inning, the rest would slot into place: Jerry Blevins for the seventh, Fernando Salas for the eighth, and closer Addison Reed for the ninth.

But nothing this season has been simple for a bullpen running on fumes. And when circumstance took that simple road map and tore it to shreds, Collins was forced to improvise.

In a 4-2 victory against the Pirates on Saturday night, Collins tasked Reed with recording the final six outs of the game, a feat he had never attempted in his big league career.

“Yeah, we made a move you don’t normally make by using your closer for two innings,” Collins said. “But we’ve got to win a game, we’ve got to scratch our way back. You never know what’s going to happen tomorrow. We had a chance to win this game. So, I went for it.”

And it worked.

Criticized for much of the season for his bullpen management, Collins hit all the right notes. When Gsellman stalled out with one out and a two-run lead in the sixth, Salas got the Mets out of a jam.

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Blevins worked a scoreless seventh.

From there, the ball belonged to Reed, who has endured mixed results as he’s taken on closing duty from the injured Jeurys Familia. But this time, Reed calmly worked through his two innings, recording his seventh save of the season.

“Things just haven’t been going our way,” said Reed, whose 114th career save also was his longest. “We’re not going to quit. We’re not going to roll over. We’re going to continue to play loose and play like we know how to play, and start a little winning streak here hopefully.”

The Mets (24-30) entered the day on a three-game losing streak, which knocked them 11 games behind the Nationals in the NL East and nine games out of the wild card. For the fourth time this season, they found themselves seven games under .500, their lowest point.

Only a victory would keep the Mets from finding a new rock bottom.

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Neil Walker, Jay Bruce and Wilmer Flores homered for the Mets. But the game followed a familiar path, with a laboring starter leaving the bullpen to carry a heavy load. This time the guilty party was Gsellman, who departed after 5 1/3 innings with the Mets leading by two runs.

With that, Collins was forced to deploy Salas earlier than he had intended. The righthander took over with runners on first and second and he fanned Elias Diaz before getting pinch hitter Jose Osuna to fly out to end the threat.

Blevins followed in the seventh, extending his brilliant season by tossing a scoreless frame and lowering his ERA to 1.42. He survived a two-out error by shortstop Asdrubal Cabrera, whose throw to first base was wide.

It also was during this inning when Collins decided on his next move. In the dugout, Collins found pitching coach Dan Warthen and verbalized an obvious reality. He had only once choice.
Five times in the last three days, the Mets needed relievers to throw more than 30 pitches. But Reed had not pitched since Tuesday. He was rested.

Soon, Collins picked up the bullpen phone and asked a simple question: “Can you do two?”

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The message was relayed to Reed. It was his first inkling that he might be asked to do something he had never done before.

He was game.

First baseman Lucas Duda helped, running down an Andrew McCutchen pop up near the fence in foul territory to begin the eighth. Later, Reed walked John Jaso, then worked out of trouble.

As Reed left the field after the eighth, he jawed at home plate umpire Stu Scheurwater about the pitches in the Jaso at-bat. But the closer kept his cool, knowing there was more work to do.

“I knew I was going to go back out there,” he said. “I didn’t want to say anything stupid.”

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In the ninth, the stillest part of Citi Field was the Mets bullpen. The game would be Reed’s game to decide. It required a season-high 36 pitches and Duda’s difficult catch. But a well-rested Reed proved up to the task.

“We needed it tonight,” Collins said. “We had to go outside the box a little bit.”