Catcher Russell Martin and closer Jason Grilli celebrate after the Pirates defeated the Reds, 6-2, in the wild-card game. Pittsburgh now faces St. Louis. (Justin K. Aller/Getty Images)

There is sports as an expression of civic pride, and there is what happened here Tuesday night, when 40,487 Yinzers pulled on black T-shirts and black jackets and black jerseys — so many of them purchased just this summer — and took part in a mass catharsis two decades in the making. When the Pittsburgh Pirates were introduced at PNC Park prior to their National League wild-card playoff game, the foremost among them turned to the crowd, touched their hearts and expressed their thanks for the support, lacking for so long.

Then the center fielder’s mother blasted out the national anthem — her son, presumptive NL MVP Andrew McCutchen, hat-over-heart nearby — and the place just came unhinged. One night doesn’t replace two decades of losing — worse, of irrelevance — and the Pirates’ emphatic 6-2 victory over the Cincinnati Reds doesn’t instantly mask the scars that remain from all that preceded it, notably and painfully a loss in the seventh game of the 1992 NL Championship Series. But it doesn’t hurt. No, it does not hurt.

“If our city ever felt they don’t make a difference,” Manager Clint Hurdle said, “all they have to do is look at the tape from tonight’s game.”

The Pirates rocked Reds right-hander Johnny Cueto with second-inning homers from Marlon Byrd (the former National) and Russell Martin, received seven lockdown innings from lethal lefty Francisco Liriano and used Martin’s second homer of the night to drive the point home in the seventh, delirium surrounding it all.

Thus, Pittsburgh rejoiced that the summer it refamiliarized itself with winning baseball will be extended — and for a bit. The wild-card win over the Reds brings a best-of-five division series against St. Louis that starts Thursday, and it ensures at least one more appearance for these Pirates at their beautiful ballpark along the Allegheny River, long one of baseball’s best venues, suddenly one of baseball’s best environments.

“It’s changed the culture of what baseball is in this town — and was,” said closer Jason Grilli, who gleefully and playfully thumped Martin’s chest after he recorded the final out. “This is what everybody talked about. To have a hand in it is pretty special. It’s humbling. . . . You can’t walk down the street without people getting crazy about the Pirates. It’s something to see.”

Tuesday night was something to see. When Cueto looked uneasy early — he escaped the first despite allowing hard, deep line drives to Neil Walker and Justin Morneau — the crowd pounced. The chants of “Cue-to! Cue-to!” came swiftly after Byrd belted a change-up out to left to open the second. When Martin followed him to the plate an out later, the serenade continued. Cueto, trying to get settled not only in the game but simply on the rubber, dropped the ball. As it rolled across the grass, he couldn’t hide from the sound of his own name.

“I’ve never seen a crowd actually get to the pitcher where he drops the ball,” Martin said. “The next pitch was — I don’t know. He made a mistake with the next pitch.”

And Martin deposited it into the left-center field seats. A 2-0 lead somehow felt like 10-0, in part because of the atmosphere. “I’ve never seen it like this,” said Byrd, an August acquisition from the Mets.

From there, it fell into place. McCutchen listened to his mother Petrina crush all the tough notes in the “Star-Spangled Banner,” then reached base four times. The Pirates drove a rattled Cueto from the game in the fourth after he allowed seven hits, four for extra bases. And Liriano shredded the Reds, retiring the first nine men he faced and making left-handers who dared enter the box look foolish. He gave up four hits and a run, walked one and struck out five.

“If you watched this one game tonight,” Grilli said, “it pretty much showcased what Liriano’s done all year long.”

Such a new feeling for Pittsburgh, to put a pitcher on the mound and a team on the field in which the entire town can have confidence. In the bedlam that preceded the first pitch, a video montage played on the scoreboard in left field with people around the city holding up signs bearing black-and-yellow letters: We Believe. After 20 straight losing seasons, it somehow made sense.

“We didn’t talk about one and done,” Hurdle said. “We talked about one and run — one and run to St. Louis.”

That’s what awaits these new Pirates. As baseball’s return to relevance in Pittsburgh has become baseball’s best story, the jerseys on the backs of those who filed in Tuesday were those of McCutchen and Grilli, Alvarez and Burnett. Clemente and Stargell, Mazeroski and Parker — they all have their place here, but for the first time in a generation, their place was in the past.

The Steelers are uncharacteristically 0-4. The boats that filled the river beyond the right field wall partied on a perfect night. The ballpark pulsed with new heroes, new story lines. The Pirates are back and can carry the town.