Ian Desmond added a two-run home run and Gerardo Parra had two a pair of RBI singles as the Rockies moved into first place in the National League West, a half game ahead of Arizona.
The Reds lost their fourth straight and seventh of nine to fall a season-worst 20 games under .500.
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Romano (3-7) took the loss by giving up five runs in five innings, including Desmond’s homer as part of a three-run fourth inning that put the Rockies ahead for good.
“I hung a curveball,” Romano said of the home run. “My off-speed stuff was really good most of the time. The change-up was the best it’s been my whole career so far. But I didn’t guys out when I needed to, didn’t put guys away when I needed to and I paid for it.”
Romano struck out six, one shy of his season high, but five of the six hits he allowed went for extra bases, including a Wolters double in the second that plated the first Colorado run.
“I gave up five runs,” Romano said. “We lost again when I pitched, so there’s really not much to say. It doesn’t really matter what I did good today. I gave up five runs.”
Jon Gray (6-6) gave up thee runs in five innings to pick up the win, while Wade Davis earned his league-leading 20th save to cap four scoreless innings of relief by the Colorado bullpen.
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Gennett drove in two of the three Reds runs with a double and a sacrifice fly, giving him 44 for the year and moving into a tie for the league lead with Chicago’s Javier Baez.
Gennett also scored the other Cincinnati run on a Jose Peraza single.
Scott Schebler and Jesse Winker, two of the members of the struggling Reds outfield, each had multi-hit games.
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Schebler was was 2 for 5, while Winkler went 2 for 4 with a walk and a run scored as part of an 11-hit Cincinnati attack one night after the Reds banged out 17 hits in a 9-6 setback, marking the first time since 1984 they lost a game with at least 17 hits.
“We get a lot of hits, we’ve just got to get some timely hits,” Riggleman said. “Getting three runs out of those hits today, that’s not enough. We didn’t play good period, still with that many hits you’d like to be able to put five or six on the board. We’ve just got to keep getting after it.”
Eugenio Suarez and Joey Votto also collected a pair of hits for the Reds, who will face the Rockies at 12:35 p.m. Thursday in the series finale.