SAN DIEGO -- In no uncertain terms, the final week of the Padres’ season has become an audition for 2020 and beyond. In his second game as manager, Rod Barajas trotted out a lineup filled with future roster hopefuls.

Lately, the organization has asked those fringe players to make a statement before the end of the season. Seth Mejias-Brean -- who had spent seven seasons in the Minor Leagues before earning a surprise September callup -- made an awfully loud one on Sunday afternoon at Petco Park.

With the game tied in the bottom of the 10th, Mejias-Brean demolished a hanging slider from Yoan López into the second deck in left field, sending the Padres to a 6-4 victory over the D-backs. The blast secured Barajas’ first career victory as manager, a day after he took over for Andy Green on an interim basis.

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Barajas was late to his postgame media session after a beer shower upon his arrival in the Padres’ clubhouse. That prompted a “costume change,” he said. But Barajas deflected the plaudits for his first win onto Mejias-Brean, the game’s on-field star.

“To see a guy who's doing everything the right way, an absolute professional, get the opportunity and take advantage of it and shine, it's been an honor to see him go out and play,” Barajas said.

The Padres inked the 28-year-old Mejias-Brean to a Minor League deal before Spring Training, and he spent the 2019 season raking at Triple-A El Paso. The long-term infield is mostly set for San Diego and it’s hard to envision Mejias-Brean finding a regular role with the club, but the Padres remain in search of utility options.

For now, however, Mejias-Brean says he’s merely trying to enjoy his first taste of life in the big leagues. He went 3-for-4 on Sunday and played a pivotal role in the Padres’ comeback from an early four-run deficit. Then, in the 10th, Greg Garcia opened the frame with a double down the right-field line, setting the stage for the walk-off.

“To be honest, I was trying to move him over,” Mejias-Brean said. “I was thinking: 'He's at second, I'm just trying to get a team at-bat going.' It just kind of happened. He hung me a slider, and I got it.”

He got all of it. The blast traveled a Statcast-projected 411 feet and left Mejias-Brean's bat with an exit velocity of 104 mph. He looked into the dugout and raised both arms as he rounded first, then was greeted with a mob and a Gatorade shower at home plate.

“This whole month has been amazing, just to be up here,” Mejias-Brean said. “And to have that to add on top of my first [walk-off] hit and first home run -- words can't describe the way I'm feeling right now.”

The Padres’ late comeback negated a rough start for Garrett Richards in his second outing since Tommy John surgery. Richards was sharp in a 1-2-3 first inning, but his command eluded him in the second, and he allowed four runs on four hits and a pair of walks over just 1 2/3 frames.

With Richards' second-inning pitch count rising, Barajas decided to err on the side of caution, giving Richards a quick hook with two outs in the frame.

“It's about health,” Barajas said afterward. “The velocity is there. He came out of the game when he did because we didn't want to run the pitch count up in that inning. We took him out of the game, but he feels healthy, he feels strong.”

Richards is expected to be a fixture in the Padres’ 2020 rotation. But San Diego's starting lineup on Sunday was otherwise filled with roster question marks, as both Eric Hosmer and Manny Machado were given the afternoon off.

Mejias-Brean and fellow rookie Ty France slotted into their lineup places. France was hit by two pitches, but he brushed those off to go 2-for-3 with a homer and a double.

“We said we were going to give some guys opportunities and mix and match the lineup,” Barajas said. “Today was a pretty different lineup out there. But they're up here for a reason. These guys are big leaguers. They've earned it. It's fun to see them get those at-bats. ... It's fun giving them that chance, it's great to see them take advantage of it.”

That same sentiment applies for Barajas. He, too, has been given a chance during the latter stages of the season, and he’ll almost certainly be in the mix as the Padres search for their new skipper. On Sunday, he tallied his first win in the big leagues after spending most of the season as bench coach and the previous three as manager at Triple-A El Paso.

“All the hard work he's put in as coach and as manager, it couldn't have happened to a better person,” said France, who played on the last of Barajas’ three division-title winning clubs with El Paso. “I'm grateful to be a part of it, and I'm looking forward to more.”