PITTSBURGH — Jack Flaherty always had the tools. Figuring out how to put them together has been the challenge for the 23-year-old pitcher since the former first-round pick arrived in St. Louis two years ago.

While Flaherty is sketchy on specifics about what what exactly he changed heading into the All-Star break, one thing is for certain: the roadblocks — mental, physical and otherwise — are all gone. Flaherty is rolling, and so are the Cardinals.

Flaherty overwhelmed the Pittsburgh Pirates in a 2-0 victory on Sunday, striking out 10 against five hits and a walk over eight electric innings to keep up a dazzling run that has turned him into the de facto ace for the NL Central leaders. Flaherty (10-7) won for the sixth time in eight starts while dropping his post All-Star break ERA to 0.76 as St. Louis pushed its lead in the division to 4 1/2 games over second-place Chicago with three weeks to go in the regular season.

“He’s in control of the conviction of what he’s doing,” Cardinals manager Mike Shildt said. “Just a lot of big league pitches consistently. Fastball where he wants it to with good life on it, and a really good slider as well. That’s what pitching looks like. Phenomenal job.”

Flaherty’s surge began with seven innings of two-hit ball against San Francisco on July 7. The Cardinals lost 1-0 that day, but the switch flipped. Flaherty has been lights out while fueling St. Louis’ sprint to first and has allowed just three earned runs 56 innings across eight starts since Aug. 1.

“(I’ve made) small adjustments, not really to my mechanics, but mentally to how I was going about things,” Flaherty said. “So little things here and there. Just tried to kind of carry it from one start to the next.”

Carlos Martinez worked a perfect ninth for his 19th save to finish off a season series dominated by the Cardinals. St. Louis won 14 of its 19 meetings with Pittsburgh, including 10 of 12 in the second half, one of the main reasons the Cardinals are heading to October while the Pirates are planning for next season.

“Guys are healthy,” Flaherty said. “We’re playing together. Playing as a team. Not letting any moment get too big.”

Paul Goldschmidt had an RBI double and Harrison Bader added a run-scoring single off Pittsburgh rookie James Marvel (0-1).