PHOENIX -- Making his sixth career MLB start, Humberto Mejía took the mound at Chase Field for the first time on Monday night. The 24-year-old right-hander will hope to pitch here many more times, as he aims to secure a permanent spot in the D-backs’ rotation in the future.

However, Mejía’s Arizona home debut didn’t go nearly as well as his previous Major League outings. But it was still a valuable learning experience for him at this stage in his young career.

Although Mejía showed glimpses of what could make him a talented big league pitcher, his night took a sharp turn in the middle innings, ending after he had allowed six runs in four-plus frames in the D-backs’ 11-4 loss to the Braves. Mejía gave up eight hits and walked two while striking out four.

Mejía, who was called up from Triple-A Reno to make his third MLB start of 2021, began strong, retiring Atlanta in order in his first seven pitches, six of which were strikes. The Braves then put runners on first and second with one out in the second, but Mejía escaped by fanning Dansby Swanson and getting William Contreras to fly out.

“Mainly, what I’ll take from this start to the next start was the way I was attacking batters early on,” Mejía said via an interpreter.

That wasn’t the case all night. In the third, Mejía retired the first two batters before giving up three consecutive hits, the last of which was a double by Austin Riley that gave the Braves a 2-0 lead. But the D-backs got Mejía the lead back by plating three runs in the bottom of the inning.

Things completely unraveled for Mejía and Arizona in the fifth, though. The Braves recorded six straight hits to open the inning -- the first four came against Mejía, whose night ended after an RBI double by Riley (his third two-bagger of the game) stretched Atlanta’s lead to 5-3.

Braves slugger Adam Duvall immediately greeted right-hander Taylor Widener by crushing a two-run 483-foot homer to deep left-center field, putting the D-backs in a 7-3 hole. By the end of the inning, Atlanta had a 9-3 lead after scoring seven runs and sending 12 batters to the plate.

“It fell apart quickly,” Arizona manager Torey Lovullo said. “I thought [Mejía] was doing a real nice job through the four innings, but then it looked like he got a little tired, a little bit of fatigue set in. He was just missing up with his pitches. I think they lacked the finish that we had seen earlier in the game.”

Mejía said he didn’t feel like he was tired, but rather that he was putting too much effort into locating his pitches.

“I think I was trying to be too perfect,” Mejía said. “I know my pitch count was up, so I knew the fifth inning was really important for me.”

Acquired in the trade that sent Starling Marte to the Marlins in August 2020, Mejía had made two previous starts for the D-backs this season. He tossed five innings of two-run ball in a no-decision in Pittsburgh on Aug. 23 and allowed four runs in six innings in a loss in Philadelphia on Aug. 28.

Having now made three starts in the Majors, 15 at Triple-A and six with Double-A Amarillo this season, Mejía feels like he’s gaining valuable experience at each level of his new organization.

“There’s going to be good days and there’s going to be bad days,” Mejía said, “but I know that for my next start, I’m going to take whatever I learned from this time into my next start.”

One bright spot for Arizona came in the seventh, when Jake McCarthy belted a pinch-hit solo home run. It was the first big league homer for the 24-year-old outfielder, who is the D-backs’ No. 23 prospect per MLB Pipeline.

However, that moment didn’t offset Arizona’s defensive struggles (which included a pair of errors) or its inability to keep the fifth from spiraling out of control.

“I’m extremely upset about our lack of ability to execute at the most critical moments at the most critical time,” Lovullo said. “We train ourselves to do that. We talk to the players about the importance of doing that. And when we don’t execute on the mound or pick up the baseball behind the pitchers, it gets extremely sloppy.”