The Cubs (25-14) increased their lead over the last-place Reds (18-24) to 8½ games.
The Cubs took a 2-0 lead in the second on a two-out, two-run double by Hendricks, who was hitting .067 (1-for-15) entering the game.
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Hendricks retired the first 10 Reds batters before giving up a home run to Joey Votto in the fourth. It was Votto’s fourth home run of the season and first since April 26. It was his first home run of the season at Great American Ball Park.
“That was good to see,” Bell said. “He’s been close for a while now. The home run was a good sign. He had good at-bats. He was taking good swings. He was aggressive. He’s going to get there, and there have been signs recently that make me think he’s really close to going the way he wants to.”
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The Cubs added a third run against Reds starter Tanner Roark in the fifth. Kris Bryant scored on a sacrifice fly by Wilson Contreras.
Roark allowed three earned runs on eight hits in five innings. He struck out six and walked one. His ERA climbed from 3.27 to 3.50.
This was the opener of a three-game series and a six-game homestand that will see the Reds play the teams with the best records in the National League. The Los Angeles Dodgers come to Cincinnati on Friday.
The Reds entered the series, having lost 14 of their last 18 series against the Cubs. The Cubs improved to 52-25 against the Reds in the last five seasons.