ST. LOUIS — By the time the Royals found momentum on their side against Cardinals starter Adam Wainwright on Friday night, they had knocked four consecutive hits and cut their deficit in half in the sixth inning.

But Wainwright did what he’s done so many times to the Royals — and other teams — over his long career and halted his opponent before too much damage was done.

Wainwright stopped the Royals’ momentum in their 4-2 series-opening loss to the Cardinals at Busch Stadium, dropping Kansas City to 2-5 on its nine-game road trip.

“He was really good early on, just keeping guys off balance,” said Ryan O’Hearn, who went 2-for-3. “He’s got that really slow curveball. Obviously, he knows what he’s doing. Doesn’t throw many balls in the middle of the plate. Once we got some things going … guys start finding barrels, and that’s kind of how it turns into a big inning. But it just didn’t happen for us.”

From the start, Wainwright carved up a lineup missing a key piece in Salvador Perez, who was a scratch after experiencing a non-Covid illness.

That damage in the middle of the order that Perez usually occupies left a big hole to fill. While the Royals knocked Wainwright around for seven hits, they only scored in one inning against him. Nicky Lopez’s flyout to left field in the sixth was the first fly ball put in play against Wainwright.

Lopez’s flyout seemed to start something, though. Carlos Santana singled on a soft liner and O’Hearn ripped a stand-up triple to put the Royals on the board before scoring on Hunter Dozier’s single.

“I’m never thinking three out of the box,” O’Hearn said with a laugh. “When I was rounding first, I wanted second and I saw the ball was still out there. I felt like I was moving pretty good today. So I’ll take that stand-up triple. I don’t remember the last time I had one.”

That would be April 23, 2019, against Tampa Bay.

“There you go,” O’Hearn said. “It’s been a minute.”

O’Hearn has three homers and 11 RBIs in 13 games since the All-Star break, and with two lefties scheduled to start for the Cardinals in the next two games, the move to play him against Wainwright paid off.

“He’s just in a confident spot,” manager Mike Matheny said. “That’s the first time we’ve really seen him like that. You just want to keep building on it. Getting us on the board is big, especially when you got that zero sitting up there, just trying to get momentum. Triples are good for that.”

That’s where the momentum would stop, though. The Royals left six on base, including three in the fourth inning after Lopez singled, O’Hearn hit into a fielder’s choice and Dozier walked. But Emmanuel Rivera lined a first-pitch cutter up the middle — and right into the Cardinals’ shift to end the frame.

Meanwhile, the Cardinals scored a run in four of Mike Minor’s five innings, building a four-run lead on seven hits against the Royals lefty. He struck out seven and walked two, but homers from Paul Goldschmidt and Tyler O’Neill did the damage.

Minor expressed some surprise at the pitches the Cardinals hit for contact. considering the scouting report against their offense. He was hit hard on almost everything, averaging a 98 mph exit velocity on the 21 curveballs he threw and 92.5 mph on 19 sliders.

“I felt like we had the game plan, and then I feel like they did a good job of knowing me and watching video, maybe, and knowing what I like to do,” Minor said. “They were sitting on stuff, looking for things. They did a good job of that, of making contact and making hard contact.”

Because the Cardinals were spitting on pitches they don’t usually take and making contact on offerings that they typically don’t, Minor said he and backup catcher Cam Gallagher made an adjustment after the second or third inning to try and switch up the game plan.

“You kind of know what location they might not hit as well, what pitches they might not hit as well,” Minor said. “And you mostly go there, and mix it up, obviously. I felt like the swings they were putting, they were good swings on balls that maybe on video we saw that they didn’t hit well. …

“Some of the takes or swings they had weren’t really corresponding with what we thought was going to happen.”