ST. LOUIS -- Zack Short has become the latest example of the Braves’ “next man up” mentality.

Short, filling in at shortstop for Orlando Arcia, had his fingerprints all over the Braves’ 6-2 win in the first game of a doubleheader against the Cardinals on Wednesday at Busch Stadium.

“It’s just the culture that this organization builds from the top down,” Short said. “You want to be a part of it. You're staying locked in no matter what.”

Making his first start since May 26, Short singled, walked twice and drove in a pair. It was his first start at short for the Braves, with his previous 12 starts coming at third.

“He got here and I told him, ‘You probably aren’t going to play a lot,’” Braves manager Brian Snitker said. “And then Austin [Riley] went down for two and a half, three weeks, and you know, he picked up that slack. He works real hard. He's a versatile kid and understands his job here.”

Short’s bases-loaded single off Kyle Gibson scored Riley and Ramón Laureano, sparking a four-run rally in the second inning. The Braves took advantage of three walks by Gibson and scored the four runs with just three hits -- all singles. Laureano grounded into a forceout to score Matt Olson to start the outburst, and Jarred Kelenic’s single scoring Forrest Wall capped it.

“It was funny, I came to the field today, for some reason I had a feeling I was … going to come up with a big situation, especially early,” Short said. “Yeah, I mean, that definitely felt good.”

Short attempted to start another rally in the fourth, working a two-out walk after falling behind 0-2 in the count. The Braves eventually loaded the bases, but Gibson escaped with a strikeout of Marcell Ozuna.

Short stepped into the shortstop role after Arcia left Monday’s game with dizziness.

With Arcia still on the mend, Short has shown himself as a sparkplug in the Braves’ lineup. He drew a key walk in the eighth as the Braves attempted a late comeback in their loss in the series opener on Monday night and has also been steady defensively.

Short’s punch at the bottom of the lineup helps turn it over for Kelenic, who continued his hot hitting in the early game out of the leadoff spot. Kelenic tied season highs with three hits, including a two-run homer, and three RBIs.

“That's part of our job, you know, to turn that lineup over and to get on for those boppers, especially with the way that Jarred has been swinging it and everybody else behind him,” Short said.

Kelenic appreciates the roles of Short and Wall as table-setters at the bottom of the lineup. The Braves’ No. 8 and No. 9 hitters reached base five combined times in the win.

“Anytime you get guys on base with the big dogs that are hitting behind me, it just gives us another opportunity to drive guys in,” Kelenic said. “And once we do that, we got a good chance of winning the game.”

It was more than enough for Braves starter Reynaldo López, who went five innings, allowed two runs on four hits, struck out five and walked four.

López (6-2) pitched out of bases-loaded trouble in the second and fifth, allowing just a sacrifice fly in each inning. They were the first runs he had allowed in his last three starts. The Cardinals’ run in the second snapped a 12-inning scoreless streak.

“I just tell myself, ‘Just calm down,’ and try to make my pitches,” López said of pitching out of those jams. “I breathe and then try to slow the game down.”

Snitker believes López’s background as a reliever helps him in those situations.

“I think it's big for him, because I see him reach back for extra when he gets in those jams and it was hard for him today,” Snitker said. “He had to really work, and kind of like things weren't real fluid. … It’s been seven days and he's had to, you know, withstand two rain delays, so very understandable.”

The Braves weren’t able to sustain the momentum, dropping the nightcap 4-1. Kelenic had three more hits, half of the team’s total, and drove in the lone Atlanta run in the eighth. It was his second straight and sixth three-hit game of his career.

But the Braves couldn’t solve Matthew Liberatore (2-2), who pitched six scoreless innings in an impressive spot start for the Cardinals. He struck out a career-high eight batters, while allowing two hits and walking one.

Braves starter Bryce Elder, called up as the 27th man for the twin bill, allowed two runs on four hits and struck out four in six strong innings.

“We're just taking it a day at a time and I'm glad we won that first one,” Snitker said. “Honestly, you know, we gave ourselves a chance late in the game in the second one and just couldn't string anything together at the beginning.”