Dave Parker's tie-breaking double in Chicago highlighted a three-run eighth inning that won for Cincinnati.
Pinch hitter Eddie Milner drew a walk off loser George Frazier (1-1) to open the eighth. One out later, Dave Concepcion singled and Parker followed with his double off the left-field wall, extending his hitting streak to 13 games.
"I was looking for something over the plate to hit hard," he said. "It was a little high, but I had already committed myself. I hit it good and thought it had a chance to go out. The wind held it up."
After the double, Frazier walked Alan Knicely intentionally, filling the bases, then ran the count to 3-0 on Tony Perez, who earlier had homered. Warren Brusstar relieved and threw ball four to force a run home. One out later, Brusstar walked Nick Esasky, forcing across another run.
The victory was the sixth in seven games for the Reds. John Stuper shut out the Cubs until they tied it in the seventh.
There were 12 walks and 12 hits in the game, causing Manager Pete Rose of the Reds to observe: "Walks can kill you. I told our pitchers to let them hit the ball. The difference was that we got the hit when we needed it."