NEW YORK -- National League Championship Series Game 5 was still in its infancy when those in the home bullpen began mentally piecing together the same puzzle as manager Carlos Mendoza. The Mets had already built a strong lead -- that was good. But starting pitcher David Peterson was throwing a lot of pitches -- that was bad.

“You’re doing the math,” said right-hander Phil Maton. “You’re running it down from nine innings, and you’re trying to figure out how we’re going to do it. And you know that somebody’s going to have to come up big.”

Those two somebodies, relievers Ryne Stanek and Edwin Díaz, combined on the final 13 outs of the Mets’ 12-6 win at Citi Field on Friday, which narrowed the Dodgers’ series lead to 3-2 and ensured the series will go back to Los Angeles. For Stanek, it was a career-high seven outs and the physical challenge of three “ups,” or times taking the mound. For Díaz, it was the final six outs of a game the Mets had to win at any cost.

“These guys are nails, man,” outfielder Jesse Winker said. “They’re ready to come in and get outs. They’re savages.”

How the heavy workloads of Stanek and Díaz will affect them later in this series remains to be seen; they’ll certainly be available for a potential Game 7, if not Game 6, but will they be as sharp? Will they be able to give the Mets as much?

For Mendoza, those are questions for the off-day on Saturday. Game 5 was about surviving, which the Mets did behind a Pete Alonso three-run homer in the first inning and a five-run rally against Jack Flaherty -- the same Jack Flaherty who had blanked them over seven innings in Game 1 -- in the third. At one point, the Mets held an eight-run cushion, which seemed like plenty. In postseason history, teams that had built a lead that large were 162-1.

Yet as the Dodgers began rallying, Mendoza found himself with little choice but to begin burning his best relievers in rather extreme ways. With several other arms unavailable due to recent workloads, Mendoza asked Stanek -- traditionally a one-inning reliever -- for seven outs. The right-hander responded with seven big ones. In a five-run game, Mendoza turned from there to Díaz, who recorded the final six outs for the first time in his postseason career.

“Today was the day, like, we’ve got to go forward,” Díaz said.

• Two high-wire acts by Mets arms in 1st, 4th frames flip momentum in Game 5

Before Game 5, Mendoza told both Stanek and Díaz to be ready for multi-inning assignments. Although the Mets’ bullpen was not necessarily in dire shape, it was three-quarters of the way there, with Maton unavailable, Peterson starting the game, Kodai Senga proving untrustworthy and others either overworked, ineffective or both. A night earlier, in Game 4, Mendoza had ridden left-hander Danny Young for three “ups” to save the rest of the bullpen. So important was that assignment that Mendoza personally sought out Young after the game to thank him.

The next morning, Mendoza sounded almost envious when discussing the Dodgers’ ability to bring hard-throwing ace reliever Michael Kopech into the fifth inning of Game 3.

“I don’t know if we have that luxury,” Mendoza said, bemoaning the relative lack of depth in his bullpen. “That’s the reality.”

Understanding his team’s strengths and weaknesses, as well as the toll that three consecutive weeks of playoff-style baseball have taken, Mendoza has relied on pitchers like Young and Tylor Megill to ease the load on everyone else. But the load on everyone else has still been heavy. Although Díaz has appeared in only two of the first five NLCS games, he’s recorded 10 total outs and thrown 52 pitches in them, on the heels of heavy usage earlier in October. Stanek has given the Mets multiple “ups” in three consecutive playoff outings, after doing it only twice during the regular season.

In a single game, these are not extraordinary feats. Piled together, series after series, week after week, relievers begin doing the math on those numbers as well. Asked how much more difficult three “ups” are compared to two, Stanek hesitated, laughed and replied: “A lot.”

“My philosophy and my approach to the game is kind of, ‘Let it all hang, and go for as hard as I can and as long as I can,’” Stanek added.

Asked if he would be available in Game 6 on Sunday, Stanek hesitated again before saying he would. Relievers will always offer to pitch, Mendoza tends to say. The manager’s job is making sure he’s pushing them in ways that can result in success.

No matter how Stanek and Díaz recover, the Mets will be short-handed in Game 6. They’ll need starting pitcher Sean Manaea to go as deep as possible. Across the way, Dodgers manager Dave Roberts spoke about remaining “steadfast in how you use your pitchers, because ultimately, it’s about winning four games in a seven-game series.” The Dodgers may have lost Game 5, for example, but they leaned on Brent Honeywell for 4 2/3 innings and didn’t deploy any of their high-leverage relievers as a result.

Advantage Dodgers in Game 6 then?

The math, as it turns out, is not that simple.

“These are must-win baseball games,” Maton said. “If guys get into trouble, we’ve got to be all hands on deck. We’ve got to find ways to win these games and stay alive.”