Sonny Gray struck out 10 while pitching five scoreless innings, and the Reds held off the St. Louis Cardinals for a 2-1 victory Thursday night.
St. Louis had won five in a row to move into a virtual tie with Chicago for the NL Central lead. The Cubs had a chance to move in front again, but they lost 7-5 at Philadelphia on Bryce Harper's game-ending grand slam.
The Cardinals wasted a prime scoring opportunity in the third when Paul Goldschmidt struck out looking with the bases loaded and two out. Gray, Robert Stephenson, Michael Lorenzen and Raisel Iglesias combined for a two-hitter.
Iglesias surrendered Kolten Wong's check-swing RBI double in the ninth before retiring pinch-hitter Matt Wieters on a fly ball to center to finish his 24th save.
Nick Senzel and Eugenio Suarez each drove in a run for Cincinnati, which stopped a four-game slide.
Dexter Fowler had St. Louis' first hit, a two-out single in the fifth. Gray then struck out Matt Carpenter to extend his scoreless streak to a career-high 18 innings.
Adam Wainwright (8-8) allowed nine hits and seven runs in 3 1/3 innings in his last start against Cincinnati on July 19, a 12-11 St. Louis win.
Luis Castillo (11-4) has allowed seven hits and two runs over 12 innings in two starts against St. Louis this season. Cincinnati won both games.