Nick Castellanos goes from boos to roars in delivering a walk-off Phillies win against the Mets to tie the NLDS

For the first five innings on Sunday, every slider that Phillies hitters chased low and away felt like another nail in their coffin.

In his first two at-bats against the Mets, Nick Castellanos had been one of their worst offenders — so much so, that holding off on a ball in the dirt earned him sarcastic cheers from the Citizens Bank Park crowd.

But in the ninth inning, after Castellanos laced a walk-off single to left field, none of the cheers were sarcastic. The right fielder’s hit — his third straight since the Bronx cheers — secured a 7-6 win for the Phillies, sending them to New York with a split in the National League Division Series. And all was clearly forgiven for Castellanos, whose fifth walk-off of the season was unquestionably his biggest.

“No heartbeat, man,” Bryce Harper said. “He just goes up there and plays his game. He’s been doing it for a long time, obviously in the big leagues, but also youth ball and things like that. So no moment’s too big.”

Castellanos didn’t get into specifics of how the boos in the fourth inning affected him, or what changes he made after he heard them.

“Just kind of frustrated,” he said. “So I guess I locked in more.”

The Mets led early, deflating the home crowd at first. They put solid at-bats on Phillies starter Cristopher Sánchez, fouling off pitches and working counts. Mark Vientos got to him in the third inning with a two-run homer on a changeup left over the middle of the plate. With his pitch count up to 88, Sánchez was lifted for José Ruiz after five innings. Ruiz allowed three hits, including a solo home run, to put the Phillies down 3-0.

» READ MORE: Hayes: Bryce Harper gives the Phillies life in win that ties the NLDS and electrifies Citizens Bank Park

But whatever number the Mets put up didn’t matter if the Phillies offense stayed stagnant. They had three singles through the first five innings, and it seemed like the sixth was about to go the same way.

With two outs, Trea Turner chased two straight sweepers outside the zone from Mets starter Luis Severino. But Turner got just enough of each pitch to stay alive, and managed to win the battle with a single to left field that brought Harper to the plate.

And who better to bring the life back into the stadium? Harper had already made three diving stops over at first base to help keep the game close. He worked a 2-2 count, before Severino put a four-seam right down the heart of the plate. Harper made him pay dearly with a two-run homer to center that sent the place into a frenzy.

Castellanos didn’t waste any time tying the game at 3, crushing a sweeper up in the zone to go back-to-back with Harper.

“I thought our at-bats were similar to last night up until that point, and then I thought our bats got a lot better,” manager Rob Thomson said. “We started getting guys back into the zone and attacking and using the field.”

Orion Kerkering gave up a solo home run to Brandon Nimmo in the seventh that put the Mets back in front, but the Phillies offense had another big inning in the eighth, kicking off the rally with a one-out walk to Harper and a Castellanos single. A triple from Bryson Stott off Mets closer Edwin Diaz and a fielder’s choice from J.T. Realmuto cashed in three runs for a 6-4 lead.

“It’s a lot of fun, especially when we’re all playing together, and we’re running after a common goal as a group in this clubhouse,” Castellanos said. “Unselfish baseball is the most fun baseball you could play.”

But the Mets wouldn’t go away. Matt Strahm pitched the ninth inning and struggled for the second consecutive night. Despite getting ahead in counts, he was unable to finish off hitters, and gave up a two-run homer to Vientos that tied it at 6. Jeff Hoffman took over and a sliding catch in right field from Castellanos finally ended the inning, setting the stage for his heroics at the plate.

“It’s a bunch of experienced guys,” Thomson said. “They’ve been through it before. They have a slow heartbeat and they understand situations and they just keep battling. It’s a very resilient club. And you can see the same thing with the Mets, they’re not going to quit either. This is shaping up to be a classic battle.”