Tyler Stephenson hit a two-run, pinch-hit homer off lefty reliever Sam Howard in the seventh inning on Monday to deliver the Reds a 3-1 victory over the Pirates in the first game of a doubleheader at Great American Ball Park.

Howard, who’s been arguably the Pirates’ most dominant reliever all season, allowed a two-out single to shortstop Jose Garcia in his second inning of work before leaving a slider up in the zone that Stephenson smashed to left field. The walk-off shot dropped the Pirates’ record to a Major League-worst 14-31 with three-quarters of the season in the books.

• Box score

“I think we had the matchups we like. [Howard] did a nice job, then Garcia got the hit there and the breaking ball got up to Stephenson and he got it up and out of the ballpark,” Pirates manager Derek Shelton said. “But we liked the matchups. He’s continued to pitch well, but didn’t execute a pitch.”

Trevor Bauer shut down the Pirates for most of the afternoon, allowing only a leadoff single and two walks while striking out 11 of the 21 hitters he faced through six innings. But Colin Moran led off the seventh by lifting a fastball from Bauer just over the right-field fence for a game-tying homer, Moran’s eighth of the season.

“We still gave ourselves a chance -- Moran hit the homer -- but I thought [Bauer] was really good,” Shelton said. “That’s why he’s so elite, his ability to differentiate between what pitch he has going on. Today, the curveball was really good.”

Right-hander Cody Ponce did his part, holding the Reds to just one run over four innings. Ponce walked leadoff man Shogo Akiyama, then retired the next 10 hitters in order before Joey Votto ambushed a first-pitch fastball to break up the no-hitter and shutout with two outs in the fourth.

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Ponce only got the Reds to swing and miss on three of his 63 pitches, but he was consistently ahead of hitters as he threw first-pitch strikes to 11 of the 14 Reds he faced. He exited the game after four innings only because the Pirates set a 65-pitch limit for Ponce heading into the game.

“I thought he was outstanding. Really, really good. His stuff was electric coming out of his hand,” Shelton said. “That’s just another really good sign. Really happy with how he threw the ball.”

The assignment of starting a seven-inning game was nothing new for Ponce, who was not made available for comment after the game. His first two starts in the Majors came in the second half of a doubleheader day, and he pitched well enough for the Pirates to win both games.

The 26-year-old right-hander earned his first Major League win against the Cardinals on Aug. 27, working 5 2/3 scoreless innings in a 2-0 victory at Busch Stadium. He led the Bucs to a 4-3 win over the Reds on Sept. 4 at PNC Park despite giving up three runs in four innings, with all the runs against him scoring on a pair of homers.

In 17 innings over five appearances this season, Ponce has put together a 3.18 ERA while allowing 12 hits and six walks. Home runs have been an issue, as he’s given up five, but the way he pounds the zone -- 64.5 percent of his pitches have been strikes -- is a welcome sight on a Pirates staff that entered Monday with the Majors’ highest walk rate this season.

There may not be many more opportunities for Ponce, who was called up as the 29th man for the twin bill, to start during the final two weeks of this season. Mitch Keller rejoined the rotation in Game 2, and the Pirates likely want to see more from Joe Musgrove, Trevor Williams, Chad Kuhl and Steven Brault the rest of the season.

All of those starting pitchers are under club control for next season, as is returning right-hander Jameson Taillon. But general manager Ben Cherington and Shelton have often talked about creating a meritocracy as they shape their roster and parcel out playing time, rewarding those who have performed well at this level.

In a small sample size, it seems like Ponce has done what he can to earn a larger role.

“We’ve talked about opportunities and guys getting opportunities and taking advantage of them. His opportunities have been limited,” Shelton said before the game. “But he’s had the spot starts, or 29th man starts, and has done a really nice job. In the short time, he’s seized his opportunities.”