ST. LOUIS -- As important as it is for Jordan Montgomery to help the Cardinals defeat their National League Central rivals in the coming weeks and months, the 6-foot-6 left-hander wanted nothing more on Sunday than to stick it to his close friends and former Yankees teammates at Busch Stadium.

After all, the Yankees are the franchise that felt Montgomery was expendable last August and traded him for center fielder Harrison Bader. As for the Yankees players, Montgomery was close with many of them after being the franchise’s fourth-round pick in the 2014 MLB Draft and pitching for the big league club for 5 1/2 seasons prior to being sent to St. Louis.

Foremost among that group was All-Star pitcher Gerrit Cole, the Yankees ace who Montgomery learned under during their time together in New York. When rain delayed and ultimately washed out Friday’s series opener, Cole and Montgomery stood outside the Cardinals’ clubhouse and had an extensive conversation.

On Sunday, when Montgomery did not allow a hit in his first 5 2/3 innings -- while limiting the Yankees to two hits and one run (none earned) overall in 6 2/3 frames -- in a 5-1 St. Louis victory, Cole was the first to congratulate him on winning the head-to-head duel.

“I was excited to face off against Gerrit because he was [scheduled] to duck me and pitch [Saturday], and then the rain happened and we ended up locking horns, and we were texting about it,” Montgomery said. “He sent me a meme of a cowboy tipping his hat. It was a fun game. I’ve got a ton of respect for everybody over there, and I’m glad we won.”

Added Cole: “The story was Montgomery. I got outpitched. He was outstanding, moving the ball well. … When he’s on, he’s really tough.”

Montgomery’s fourth straight win -- and his second over the Yankees in as many tries -- allowed the Cardinals to win the three-game set and capture their first series victory at Busch Stadium since May 18-21 against the Dodgers. The Cards and Yanks played before 133,759 fans, with sellout crowds packing Busch for each contest.

Looking for dependable pitching last August to shake their team out of a malaise, the Cardinals were shocked when the Yankees made Montgomery available at the Trade Deadline. His first start as a Cardinal just so happened to come against the Yankees on Aug. 6, 2022, and St. Louis earned a 1-0 win en route to sweeping the series.

Manager Oliver Marmol is hoping this strong series against the Yankees will propel the Cardinals to a stellar second half, similar to 2022.

“It can, and our hope is that it does,” Marmol said of a Cardinals club that sits in last place in the NL Central. “We came up short in that second game against Houston, but we easily could have taken two out of three there. Then, we took this series. So we hope we can build off this momentum.”

Montgomery got help from rookie Jordan Walker and second-year standout Brendan Donovan. Walker, who saw his 17-game hitting streak end in Game 1 of Saturday’s doubleheader, drilled a single back up the middle off Cole for the first run of the day. Donovan, who was back in the lineup after missing two games with a right arm injury, had hits in his first three at-bats, including a two-run homer in the seventh inning.

Working with catcher Andrew Knizner for a fourth straight start, Montgomery struck out six Yankees and didn’t surrender a hit until Gleyber Torres doubled to right field with two outs in the sixth inning. According to Elias Sports Bureau, it was the deepest Montgomery has gone in an MLB game without giving up a hit, topping his five-inning effort against the Reds at Yankee Stadium on July 25, 2017.

On Sunday, Montgomery got 22 swings and four misses on his 53 sinkers, five swing-and-misses on his curveball and four whiffs on his changeup. It’s the tailing and dropping sinker, Knizner said, that makes Montgomery so difficult to square up.

“Not only the movement of the pitch, but it’s coming from a big body and it’s coming downhill right at you,” said Knizner, who had an RBI single off Cole in the fourth. “As a hitter, it’s kind of intimidating seeing Monty throwing that sinker down right at you. You can know it’s coming, and it’s still hard to hit because it’s so heavy and it has so much downward plane movement. It’s his bread and butter, and it’s something we can lean on.”

Added Montgomery: “I was expecting them to come out swinging, so I was just going to stay at the bottom of the zone and let them hit it into the ground.”