ST. LOUIS (AP) -- Rookie Tyler Mahle threw five innings, Eugenio Suarez hit a grand slam and the Cincinnati Reds beat the St. Louis Cardinals 6-0 on Wednesday night.
Jesse Winker added a home run and Joey Votto had two hits and drove in a run for the Reds, who had lost four of their last five games.
The Cardinals had won four straight and eight of nine.
Mahle (1-2) tossed allowed four hits, striking out four and walking three in earning his first major league win. The right-hander, who was making his fourth career start, threw 100 pitches and was able to strand eight runners.
Cardinals starter Jack Flaherty (0-1), also a rookie right-hander, allowed three runs and four hits over 4 1/3 innings. He struck out three and walked two.
Winker, the Reds rookie right fielder, opened the game with his fifth homer of the season. Winker ended the first inning with a diving catch that saved a run.
The Reds scored five runs in the fifth, all coming with two outs, and all coming after the third out of the inning was overturned upon replay review.
Cardinals shortstop Paul DeJong made a diving stop to snare a grounder from Zack Cozart. He flipped to second base for the third out, but replays showed Mahle beat the toss to the base.
Votto then smacked a bases-loaded single to left field off left-handed reliever Ryan Sherriff to make it 2-0. Suarez followed with a grand slam, his 25th homer of the season, into the Reds bullpen in left field to make it 6-0.
The Reds bullpen backed Mahle's start with four innings from Kevin Shackelford, Michael Lorenzen and Luke Farrell. The Cardinals managed just one hit over the final five innings.