All five home runs belted by the Astros off Reds starter Justin Lehr, including three in the third inning, were with the bases empty. Houston lost for the second time this year after hitting five homers in a game.
Jeff Keppinger swatted a pair of homers, and Carlos Lee, Kaz Matsui and Geoff Blum also homered for the Astros, who were 0-for-8 with runners in scoring position. The Reds got solo homers from Jonny Gomes and Drew Stubbs.
"They were all for nothing," said Keppinger, the former Reds player who started at third base. "It doesn't really matter if you don't win. This is a ballpark for home runs. It's not very big and the ball carries well. We happened to hit them today. The first two days [of the series], we didn't hit many, but we did today."
Houston managed only two baserunners after Blum and Keppinger hit back-to-back homers in the fifth. Cincinnati pitchers retired 14 of the final 16 batters, with four relievers combining to hold the Astros to one hit in the final four innings.
"You have to do the little things," Keppinger said. "That's what it comes down to in this game. You get on the road and you have to battle. You have to get bunts down and get first to third [on base hits] and move runners and try to get the big hit. It just seems like when we get on the road, we don't get those big hits."
Left-hander Wesley Wright (3-3) suffered the loss by allowing both batters he faced in the seventh to reach via singles, but Fulchino was on the mound when the go-ahead run scored. He bounced a slider that ricocheted off catcher Chris Coste and rolled toward the third-base dugout to allow Votto to trot home.
Otherwise, Fulchino was terrific. He faced seven hitters and had a career-high six strikeouts and one walk in his fourth outing in five games.
"It's a funny game like that sometimes," Fulchino said. "It's been a tough season of ups and downs, but I felt good. I pitched three days in a row and had the day off, and I felt good. It's nice to have some cooler weather."
Gomes homered to left field off Astros starter Yorman Bazardo in the second to put the Reds ahead, 1-0, but it wasn't long before the Astros got into the long-ball act themselves. Matsui led off the third with a homer, and Lee and Keppinger added solo homers in the span of two at-bats to make 3-1. It was the first time since May 2, 2008, that the Astros hit three homers in one inning.
Lee's homer came moments after Hunter Pence was thrown out at third base trying to stretch a double into a triple.
"That was a bad baserunning move, especially with the situation," Pence said. "I was too aggressive. With nobody out, you have to be 100 percent sure you're going to be safe. Or don't do it."
Cincinnati tied the game in the third on a homer by Stubbs and a sacrifice fly by Scott Rolen and took a 4-3 lead on Lehr's squeeze bunt in the fourth that scored Wladimir Balentien from third base.
"The squeeze bunt was the right pitch, but not a real good one," Cooper said. "It's one of those unfortunate things. It seems like things are going the wrong way for us. We need to get it straight, and maybe we can use [Thursday's] day off to get it straight."
Blum and Keppinger hit back-to-back homers with one out in the fifth to give Houston a 5-4 lead. Lehr became the first Reds pitcher to allow five homers in a game since left-hander Brandon Claussen in 2005. The Reds tied the game at 5 on Stubbs' two-out RBI single in the sixth off Wilton Lopez.
"We just couldn't seem to put a whole lot together other than the solo jobs," Cooper said. "They seemed to get a lot of two-out base hits in RBI situations, and all of ours came on solo jobs."