Winker's fourth home run of the season greeted left-hander Randy Rosario, who was brought on to face Winker after Cubs starter Kyle Hendricks exited with one run in, the bases loaded and two out.

It was the Reds' fourth straight win and seventh in their last nine games. The Cubs, who began the night in a first-place tie in the National League Central, have lost three of their last five but have won 17 of their last 26.

The Reds' outburst made a winner of starter Matt Harvey (2-5), who matched his longest stint of the season by going six innings. He struck out six, while giving up two runs on five hits and a walk. He also hit two batters.

The only runs he allowed came on a two-run double by Javier Baez in the third inning. Baez moved into a tie with Anthony Rizzo for the team lead with 48 RBIs.

Hendricks (5-7) used a steady diet of changeups to keep the Reds off balance for five innings, but he ran into trouble in the sixth.

Hendricks walked the Reds' No. 9 hitter, Billy Hamilton, to lead off the inning. Two outs later, he walked Joey Votto on four pitches. Scooter Gennett, who began the day leading the league in hitting, singled on a changeup to load the bases.

Hendricks left after walking Eugenio Suarez to force in a run and cut the lead to 2-1, giving the Reds third baseman his 55th RBI of the season, good for the team lead and second in the league.

After Winker's slam, the Reds added three more singles against Rosario. The third of those, by Hamilton, drove in Adam Duvall with the sixth run.

The Cubs threatened right away in the top of the seventh, loading the bases with two out against Reds reliever Michael Lorenzen, but lefty Amir Garrett came on to strike out Rizzo on three pitches to end the threat.

The Cubs also tried to rally in the eighth, but right-hander Jared Hughes replaced Garrett with two outs and runners on first and second, and he struck out pinch hitter Albert Almora Jr., who began the night third in the league in hitting at .324.

Jason Heyward had four hits for the Cubs, who outhit the Reds 8-7.

Hughes finished for his fifth save, striking out two in 1 1/3 innings.

Rob Zastryzny and Justin Hancock each threw an inning of scoreless relief for the Cubs.

--Field Level Media