The nostalgia from before the first pitch to beyond the last one for the Mets’ roots during last Thursday’s home opener was kind of sweet — the baseball version of a student spending some time during his first week of college leafing through his high school yearbook or a shoebox filled with photos of his hometown friends to remind him of his roots even as he embarked upon a more fruitful and goals-fulfilling future.

The nostalgia Saturday, Sunday and Monday was of the self-destructive variety — the equivalent of the Mets not just heading home for the weekend but partaking in the type of behavior that would never allow them to make the long-discussed fresh start.

All of which made Tuesday’s doubleheader sweep a much-needed reminder of the new era the Mets are trying to jumpstart. A come-from-behind walk-off 4-3 win over the Phillies followed by a 4-0 victory in the nightcap didn’t save the Mets’ season, which probably wouldn’t have been ruined with one or two losses.

The Mets are no longer getting by with low-ceiling internal options and imported veterans being paid for past performance. Shortstop is now the domain of Francisco Lindor, not Ruben Tejada or Wilmer Flores or Amed Rosario. The sight of Taijuan Walker, the first Mets player to wear no. 99 since Turk Wendell, leading the Mets out of the dugout and leaping over the first base line in Wendell-esque fashion before he started pumping 96 mph sinkers last Thursday is a reminder he’s being paid as much this season as Rick Porcello was scheduled to be paid last season.

There’s too much talent on the roster to expect the poor performance in anything resembling clutch situations last Thursday and Saturday — the Mets had one hit in 28 plate appearances with runners on against the Marlins — to be anything more than an early-season, small sample size blip. Soon enough, the Mets will no longer have to mount rallies in agonizingly piecemeal and sometimes hilarious fashion. Who didn’t think of Mike Piazza dazedly waving home Melvin Mora with the game-winning run on a wild pitch in game no. 162 in 1999 last Thursday, when Michael Conforto drew the world’s flimsiest hit by pitch to force home the winning run in the ninth inning?


And yet…these are the Mets, where seasons have lately been defined by April swoons and the drama, often of the self-generated kind, rarely had a short shelf life.

The boos cascading upon impending free agent Conforto after another fruitless at-bat with runners on base Saturday evoked memories of the summer of 1998, when the chances of Piazza re-signing with the Mets seemed to ebb and flow depending on whether or not he delivered in RBI situations.

Until the hits from Conforto and others begin falling, it’s tough not to think of the “it’s just a little early, it’s still good, it’s still good” optimism that accompanied the slow starts for teams which went on to finish among the bottom five in the NL in runs scored 10 times in the last 20 years.

And perhaps what was once said in jest — the Mets place too much pressure on themselves trying to support Jacob deGrom — is starting to look like a great topic for a dissertation for a sports psychologist. The Mets have scored two runs in two starts in support of deGrom, who is 0-1 with an 0.64 ERA. He went at least seven innings, gave up two runs or fewer and didn’t get the win Saturday for the 34th time since his big league debut in 2014.

DeGrom was on the bench Tuesday, when the Mets, playing for the first time since Saturday, mounted an eighth-inning rally in the opener that was a little too close to Thursday’s comedic comeback — Jonathan Villar’s clean walk-off single over a drawn-in outfield was preceded by Pete Alonso’s leadoff RBI single (snort), a force out, a walk and an infield single — before the lineup offered some sustained stirring in the fourth inning of the nightcap. A three-run fourth, produced via three singles and a double, marked just the second time this year the Mets have scored more than two runs in an inning.

“I think the guys know they can connect quality at-bat after quality at-bat and they can erupt in one inning,” manager Luis Rojas said. “This is how we are, this is our identity.”

The Mets will be in even better position if their identity was revealed by Marcus Stroman tossing six scoreless innings on what amounted to one day’s rest in the second game. Stroman merely taking the mound ensured the biggest controversy of the nascent Steve Cohen era — the inexplicable decision to start Stroman Sunday, when a downpour forced the game to be postponed after nine pitches and left Rojas to talk about the convoluted process involving an independent meteorologist instead of Sandy Alderson or Zack Scott — came and went in a couple news cycles.

There was probably some self-preservation in Stroman coming back on such short notice — pitching Tuesday spared him a Friday date in Colorado and the heavy Sunday-Tuesday workload might be enough to buy him the extra day of rest that would allow him to avoid Coors Field entirely — but regardless of how it happened, there won’t be any time spent between his starts parsing his frustrated rain delay Tweets. Terry Collins should have been so fortunate during Matt Harvey’s attention-starved heyday.

“I think the guys believe,” Rojas said of the offensive outburst, on a night when channeling a long-ago marketing slogan qualified as the type of nostalgia that can help remind the Mets where they were without returning there.