ST. LOUIS -- When he last started a game for the Cardinals seven days earlier, Matthew Liberatore was told to hurriedly head to the bullpen to warm up just as he was about to join teammates in line for the playing of the national anthem.

This time around, Liberatore was informed late Tuesday night that he’d be the Cardinals' fill-in starter in Wednesday’s Game 2 of a doubleheader. While that was still far from ideal, the added preparation time seemed to make all the difference to the 6-foot-4, 215-pound left-hander who just might have earned a bigger role in the rotation in the future.

A long-time starter who was converted to a reliever this season, Liberatore limited the Braves to just two hits over six scoreless innings and struck out a career-best eight as the Cardinals won 4-1 in the nightcap of a doubleheader at Busch Stadium.

“I don’t really care either way [in terms of prep time for a start] because the job is still to go out and execute pitches and help this ballclub go out and win a game,” said Liberatore, whose five starts this season have come as either an injury replacement or a doubleheader fill-in. “I’m happy any time I get that opportunity [to start].

“With today being a day-night doubleheader and knowing that I was pitching the second game, I got to sleep a little extra and show up a little later. Not having to lock it in for nine innings [of the first game] and then starting the second game, that does make a big difference.”

Liberatore’s work allowed the Cardinals to win for the fifth time in six games and win the three-game series against the Braves, the team just ahead of them in the Wild Card standings. Also, the series win came on the heels of the Cardinals sweeping the Giants. They’ve won seven of eight at Busch Stadium.

“With all the rain delays, doubleheader, bullpen game and all of it, guys just stayed locked in,” said Cardinals manager Oliver Marmol, whose club has gone 26-14 since it bottomed out at nine games below .500 [15-24] on May 12. “They’re not giving in to a lot. It doesn’t matter -- delays or not starting on time -- once that first pitch is thrown, guys are locked in. They’re not giving away a whole lot. If the opposition is giving us anything, we’re taking advantage of it and playing good baseball.”

Expected to throw just 60-65 pitches as the spot starter for the night, the 24-year-old Liberatore seemingly got stronger as the game went along, allowing the Cardinals to stick with him through six innings. Liberatore struck out the side in his final inning of work, getting Luke Williams and Jarred Kelenic swinging and Braves star Ozzie Albies looking to cap his night.

“He was in control of that whole outing and the game looked slow to him,” Marmol raved. “And, man, he was on the attack. He was incredible. … He took advantage of this opportunity and took a huge step forward.”

Liberatore’s depth into the game was welcomed by the Cardinals, who had to use their bullpen to cover five innings in a 6-2 loss in Game 1 earlier in the day. He used his hard-breaking slider to get 10 swings and misses. Also, Liberatore showed tremendous improvement against right-handed hitters, who came into the game hitting .310 with a .942 OPS off him this season. On Wednesday, Liberatore held Atlanta’s right-handed hitters hitless in 14 at-bats.

“[Atlanta lefty] Kelenic got the two hits -- of all people,” Liberatore cracked. “I was able to establish the cutter in, my command of the fastball was really good and obviously that slider being a put-away pitch, it was really good, too. The combination of those three things kind of kept them at bay.”

Even though he has thrived this season as a short-burst reliever who is able to matchup primarily against left-handed hitters, Liberatore said his dream is still to be a starting pitcher. Whether that means continuing to be an injury replacement as a starter or one who gets the traditional four days to prepare for each start, Liberatore said he still thinks of himself as a starter and thinks like a starter regardless of the role.

“I’ve been a starter for 15 years and I’ve been a bullpen guy four months total between last season and this season, and I’ve tried to embrace that [reliever] role and I’ve gotten comfortable out there [in the bullpen],” he said. “But, at heart, I’m a starter and I really enjoy trying to go through a lineup multiple times and try to outthink guys and outcompete guys.”