ST. LOUIS -- Consistent success in one-run games, much like good clubhouse chemistry, can often be difficult to pinpoint. Winning or losing in those spots usually comes because of a confluence of events and not just one grand, seminal moment.

On Sunday, the Cardinals saw their chances of a much-needed series win against the rebuilding Reds slip away because of a series of mistakes bunched together in an eighth inning that was emblematic of a season gone so very wrong.

Tied at 3, reliever Jordan Hicks walked Cincinnati speedster Elly De La Cruz to lead off the decisive inning. It was the seventh first batter Hicks has walked this season, tied for the second most such free passes in all of baseball. Hicks then proceeded to work the count full to Spencer Steer, and that gave De La Cruz a chance to get a running start that kept the Reds out of the double play on Steer's groundout.

From there, catcher Willson Contreras went down to one knee for a low-and-away pitch from Hicks that instead tailed back inside. When the ball hit off Contreras’ mitt for a passed ball, De La Cruz easily moved up to third. And when shortstop Paul DeJong threw to the wrong side of home after fielding a routine grounder with the infield in, it allowed De La Cruz to score what proved to be the winning run in a frustration-filled 4-3 loss at Busch Stadium.

Again, no decisive swat or a major defensive gaffe, but instead a series of missteps that, when stacked upon one another, added up to more frustration for a Cardinals squad that is having more and more difficulty pinpointing why its season keeps slipping away.

“The only common denominator we’ve had is that we’re finding ways to lose,” starter Adam Wainwright said. “We lose in different ways every game. … It is seemingly a thing where we’re losing by one [run] a lot.”

On the heels of their latest head-scratching defeat, the Cardinals dropped to 7-15 in one-run games. Also, they frittered away yet another series they needed to win to start a potential climb out of the NL Central basement. Since ending an impressive stretch where they won 10 of 13 against the Cubs, Red Sox, Brewers and Dodgers, the Cardinals have gone 6-12 while losing four series.

“We have to be perfect to win right now,” manager Oliver Marmol said. “We don’t have the luxury of giving up extra outs, making a mistake or walking a guy. That’s where we’re at at the moment. It feels like we can’t make a mistake because the other team has been able to capitalize on it every time. We can’t give up outs or the leadoff walk. We’ve got to execute better.”

The Cardinals might have been able to win on Sunday if Wainwright, the 41-year-old who was trying to nab career win No. 198 for a third time, could have escaped the sixth inning unscathed. Wainwright breezed through five innings, but the sixth proved troublesome. Wainwright walked De La Cruz, allowed him to steal second base and surrendered a two-out single to Tyler Stephenson on an 86-mph sinker that stayed up in the zone.

“I was one pitch away from getting out of there up 3-2, going six innings and only giving up two runs,” said Wainwright, who has failed to get past 5 2/3 innings in any of his seven starts this season. “The soft bloop drops and the chopper to first and I’m out of the game. Only two balls that go for hits were hit hard. I made some good pitches, but I had some bad luck, too.”

Wainwright agreed with Marmol’s assessment that the Cardinals are feeling the pressure of having to play perfect baseball. That pressure has manifested itself at the plate where the Cardinals have often struggled with tasks such as moving runners over or mustering productive at-bats when situational hitting is the only ask.

Against the Reds, the Cardinals were 2-for-22 with runners in scoring position and they stranded a whopping 25 runners.

“That’s the difference between where we want to get to and where we are at the moment, our ability to come up with a big hit with runners in scoring position and then add on and build off that momentum -- that just hasn’t been the case and we have to find a way to do that,” Marmol said. “If we’re going to get out of this and start playing good baseball, we’re going to have to start driving in some runs in those situations, bottom line.”