Arizona Diamondbacks pitcher Zac Gallen points during his start against the St. Louis Cardinals at Chase Field. (Arizona Sports Photo/Felisa Cardenas)

PHOENIX — Arizona Diamondbacks ace Zac Gallen told manager Torey Lovullo he didn’t feel his sharpest during Sunday’s game, like he was laboring out there against the St. Louis Cardinals.

He only managed to give the D-backs six shutout innings with seven strikeouts in a 5-0 victory at Chase Field, lowering his ERA to 1.64 through four starts.

“You guys heard me say a lot last year, I felt like I had a good outing and didn’t feel my best,” Gallen said. “I think it’s just me really just striving not for perfection but for excellence. I think I know what it feels like, what it takes. … Honestly, things are starting to click a little bit more and I’m able to make the adjustments a little bit quicker.”

Gallen faced some adversity early, as catcher Tucker Barnhart called the second inning the turning point in the game. After a 1-2-3 first with two strikeouts on 10 pitches, Gallen surrendered a lead-off double to Nolan Arenado.

St. Louis loaded the bases with one out, but Gallen caught longtime NL West foe Brandon Crawford looking on the eighth pitch with a fastball and induced a groundout to end the inning.

Sunday was Barnhart’s first time catching Gallen in the regular season, and the veteran backstop said Gallen’s command is “crazy (good).” Barnhart credited Gallen’s ability to throw four pitches for strikes and collect outs.

“The second (inning) comes around, it just felt like the game was on the line to me,” Barnhart said. “I think Zac did a hell of a job of getting out of that with nothing. It’s rare to get out of that with nothing, but you’re trying to limit the damage as much as possible. Try to give up one, not two; two, not three; whatever the case may be and being able to get out of there with the zero is huge.”

Willson Contreras started the fourth with a double and reached third with one out. Gallen threw four curveballs to Ivan Herrera and struck him out, which he said was Barnhart’s call — Barnhart said he called much of the game, but there were moments when Gallen would beat him to the PitchCom.

Crawford popped up, and Gallen was out of another jam. Gallen finished with a pair of 1-2-3 innings, retiring his final nine hitters overall.

Lovullo said he pulled Gallen at 90 pitches since the ace’s pitch count was high Monday against the Colorado Rockies (108 pitches) and the score was 5-0 at that point. Joe Mantiply and Bryce Jarvis finished off the final nine outs with no hits allowed.

Diamondbacks manager Torey Lovullo explains the decision to take Zac Gallen out after six scoreless innings at 90 pitches. pic.twitter.com/25kTnUOf6k

— Arizona Sports (@AZSports) April 14, 2024

“I think the breaking ball was elite, it was strike-to-ball, bottom of the zone, seemed like he could throw it anywhere he wanted at any time,” Lovullo said. “Fastball came out real hot, real aggressive and he established that and then went to work with a secondary stuff.”

Gallen said his curveball felt better in Colorado, which he judges by repeatability more than movement. Barnhart thought it was great, and the Cardinals swung at 11, whiffed six times and only put one in play.

So what is Gallen looking for in order to feel 100%?

“‘I said it numerous times last year, just some things delivery-wise weren’t adding up and I feel like I was getting really close and just going down the wrong rabbit hole,” Gallen said.

“A lot of things, timing, rhythm, tempo, all your normal stuff pitchers talk about. I think just addressing bad habits, maybe habits I thought were good and worked for me at one point and now they maybe became a bad habit, trying to get out of that.”

In all four starts this year, Gallen has exited with a lead.

That lead took a while on Sunday, but the Diamondbacks broke out against Cardinals starter Miles Mikolas in the fifth inning, scoring at least five runs in a single frame for the fourth time this season.

The D-backs had nine hitters dig in with four hits, two walks and a sacrifice fly.

Christian Walker started with a single, his second of three hits on Sunday, followed by a Joc Pederson double down the right-field line.

Jace Peterson followed with a sac fly to left, a ball not hit particularly deep, but Walker tested outfielder Brendan Donovan, whose throw was just up the line enough for Walker to dive in.

Jake McCarthy followed with an RBI double to right, and after two walks, Corbin Carroll had a chance to break it open.

Carroll punched a first-pitch fastball from Andre Pallante through the four-hole to score two more runs, and Ketel Marte scored the fifth on a wild pitch.

The base running was aggressive and made a difference with Walker and Marte’s reads, along with stolen bases from McCarthy and Carroll.

Carroll avoids injury

A stressful moment for Lovullo came in the sixth, as Carroll and McCarthy were going all-out for a ball in the right-center field gap and collided. McCarthy caught the ball and popped up, but Carroll was down for a moment before getting up and jogging off.

Lovullo said Carroll fell on his left wrist but that no X-rays were done and the outfielder would be in Monday’s lineup.

Scary collision between Corbin Carroll & Jake McCarthy. Both guys seem to be ok and got up. An amazing catch and lucky both guys seem to be fine pic.twitter.com/zDTEUwHQSS

— Dalton Feely (@dfeely14) April 14, 2024

Who do the Diamondbacks play next?

The D-backs host the Chicago Cubs Monday-Wednesday, the club they defeated six of seven times in key September matchups.

Merrill Kelly, Tommy Henry and Brandon Pfaadt are lined up for Arizona in order, while Chicago’s probables are Ben Brown, Kyle Hendricks and Jordan Wicks.

Montgomery incoming?

Jordan Montgomery threw 71 pitches through 3.2 innings for Triple-A Reno on Saturday, and Lovullo said his next start would probably be with the Diamondbacks.

Montgomery is lined up for Arizona’s series at the San Francisco Giants next weekend, as he previously mentioned Friday as the target date.

Lovullo was not concerned with Montgomery’s seven earned runs Saturday, saying the veteran was focused on feeling out his fastball.