Connor Joe welcomed starter Luke Weaver off the injured list by launching a three-run home run over the Reds’ bullpen in left center field in the first inning.
Jack Suwinski followed with a towering home run to right, marking his fourth homer in as many games and fifth this season.
The offense cooled down over the remainder of the game as an Austin Hedges single in the second marked the fourth and final hit for Pittsburgh.
Roansy Contreras picked up the 10th straight quality start by a Pirates pitcher after throwing six-and-two-thirds innings of one-run ball. He collected eight strikeouts while limiting the Reds to five hits and two walks.
Contreras was also helped in the seventh by Ke’Bryan Hayes, who started a 5-4-3 double play that was anything but routine.
Additionally, Contreras got some help from his slider. According to MLB.com’s Justice delos Santos, he generated 14 whiffs with his slider, along with seven swinging strikeouts.
Robert Stephenson relieved Contreras in the seventh and struck out the only hitter he faced. Colin Holderman took over in the eighth inning but struggled with his control and allowed two earned runs on three hits.
David Bednar earned his league-leading ninth save with a spotless ninth.
Game two of the series is Friday night. Mitch Keller toes the rubber for the Pirates at 6:35 p.m.