The Cardinals asked J.A. Happ to be serviceable: to paper over the second half of the season as their injury-depleted rotation tries to make both a last-ditch run for the postseason and, more simply, to fill out the remainder of their innings.

Instead, Happ has been stellar.

The left-hander started his night with three perfect frames and ultimately allowed only one hit -- a solo homer -- in Tuesday’s series-opening 4-1 win over the Pirates at PNC Park. In all, Happ’s line went: six innings, five strikeouts, 86 pitches (53 strikes) and just three baserunners, thanks to a pair of walks along with Hoy Park’s solo shot.

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The remainder of the Cardinals’ bullpen followed Happ’s lead, not allowing a hit the rest of the way for the club’s first one-hitter of the season.

“It sets a tone, man, that mound sets the tone,” said St. Louis manager Mike Shildt. “You look and it's where it starts. J.A. did a great job tonight. We jumped on, got an early lead. … [Happ] set the tone for the tempo of the game and set the tone for the tempo of the series.”

The series opener not only provided a positive glimpse for the Cardinals’ rotation, which will get Jack Flaherty back on Friday and Miles Mikolas next week, but a wholly positive sign for Happ, who carried a 6.77 ERA to St. Louis at the Trade Deadline. Since then, he has tossed 11 innings and allowed just three earned runs.

But perhaps this should have been expected. Happ, a former Pirate, has been sensational against his former club and in his former ballpark. As a Twin in April, the lefty took a no-hitter into the seventh inning against the Bucs and finished with 7 1/3 scoreless frames. With Tuesday’s result, he owns a career 2.84 ERA at PNC Park and a 2.54 mark against the Pirates.

“I don’t think it’s anything against this team per se,” Happ said, “but when I did play here … great memories from those couple months. My son [J.J.] was born here, and just some fun memories kind of coming back and being downtown in the area here. And beautiful ballpark, of course.”

The numbers are clear, though: Happ owns a 7.13 ERA this season against teams not from the Steel City. Against the Pirates: 0.68.

“I think both times we’ve faced him, he’s executed balls on both sides of the plate. He’s given us trouble,” said Pirates manager Derek Shelton. “To say in his other starts, I don’t know. But both of his starts against us, he’s really executed balls to both sides … especially the fastball to both sides of the plate.”

It also helped that on Tuesday that Happ was handed an early margin for error, buoyed by solo homers in the first and second innings, a leadoff shot from Tommy Edman and one from a snake-bit Paul DeJong. A three-hit game for Dylan Carlson was simply gravy on a night full of positive outlooks.

Such outlooks were no more positive than they were for Happ, who finds himself unlocking the formula St. Louis has seemingly brewed for its active crop of starters, each of whom is at least 37.

Adam Wainwright has served as the proclaimed “bulldog” that’s made him a Cardinals legend; Wade LeBlanc went from released three times since March to a sturdy 3.12 ERA; Jon Lester appears to be finding the pieces to provide depth; and Happ, slowly but surely, has started to turn around a season in which he once led the Majors in earned runs.

“With guys that have been in this league, guys that have had experiences and successes, we just sat all those guys down initially and said, ‘Hey, where are you and what's going on? You tell us; we don't know you. And what do you need from us?’” Shildt recalled.

Such communication and rejuvenation of veterans has helped the team in spades -- not just getting through the innings of what’s been an injury-marred season, but rattling off far more wins since St. Louis’ disastrous June.

Happ, for his part, doesn’t say he’s changed much; he’s just “trying to just remember to stay convicted in every pitch.” But he’s doing what he can to be part of a cornerstone Cards strong suit -- starting pitching -- that’s set to get healthier and stronger soon.

“It's a steadying presence,” Shildt said. “It's a steadying presence of having guys that have been there, done that, under control. It really does start on the mound.”