PHOENIX -- Patrick Corbin was cruising along Wednesday afternoon, mowing down the Reds for 6 1/3 innings.
And then -- in seemingly the blink of an eye -- it all unraveled for the D-backs' left-hander, as the Reds struck quickly for pair of home runs en route to a 6-2 win and a sweep of the three-game series at Chase Field.
The loss was the sixth in a row for the suddenly reeling D-backs, who finished their 10-game homestand with a 2-8 mark.
"We had a terrible homestand," manager Kirk Gibson said. "We scored 13 runs in our last six games. Not a lot is going right, so it's not a good feeling. Everyone's searching, and the more you search the tougher it gets at times. We need to stop the streak right now. We need to get that feeling back. Guys are frustrated. It's been a while."
The D-backs entered the homestand riding a four-game winning streak and were just 4 1/2 games off the pace in National League West. They ended it nine games behind the first-place Giants, who were playing in Houston on Wednesday night.
"We're not happy about it," D-backs outfielder Chris Young said. "It's definitely not what we had planned. But sometimes things don't work out the way you want them to and you have to find a way to be mentally strong through it to understand the importance of this road trip we have coming up and try to make the best out of it.
The D-backs jumped on top, 1-0, in the first inning when Aaron Hill walked and eventually scored on a balk by Mat Latos.
In the fourth, the D-backs pushed their lead to 2-0 when Justin Upton singled with one out and one out later was driven in by Jake Elmore's double to left. The RBI was the first of Elmore's big league career.
That appeared to be all that Corbin would need. The rookie held the Reds to just two hits -- a third-inning single by Latos and an infield single by Zack Cozart in the sixth-- through the first six innings.
"He was rolling," Gibson said.
The seventh started off innocently enough, with a Jay Bruce flyout on the first pitch, but it spiraled out of control for Corbin in a hurry after that.
"It happened very quick," Gibson said.
After watching Bruce swing at the first pitch, Corbin figured the next batter, Todd Frazier, would not be hacking at his first offering, so he tried to get ahead with a fastball.
"Kind of left it a little bit [over the] middle," Corbin said.
Frazier's aggressiveness paid off with a double, and Corbin then fell behind Chris Heisey, 3-0, before Heisey blasted a home run into the center-field overhang to tie the game at 2.
"He pitched well," Heisey said of Corbin. "The home run he gave up to me was one of the first at-bats where he fell behind. He was [ahead] 3-0 and then 3-1. I was sitting on a fastball and I got it. He was pitching ahead, pitching in, pitching out with his fastball. We knew he threw a lot of fastballs. We finally got to him."
Corbin (5-6) rebounded to strike out Miguel Cairo, but Dioner Navarro followed with a homer down the left-field line to give the Reds a 3-2 lead and chase Corbin from the game.
"I was able to throw all my pitches today and located really well," Corbin said. "They're an aggressive team so I had to throw everything today, and that's what I was able to do until the seventh."
It is all part of the learning process for a rookie making his 11th big league start.
"He is a young kid and we've seen another game or two that he's been [at a] low pitch count getting into the seventh where that's happened," Gibson said. "That's something he's going to have to learn how to deal with. He threw an exceptional game up to that point."
Cincinnati added three insurance runs in the eighth on a two-run homer by Brandon Phillips and a solo shot by Heisey off reliever Matt Albers.
"They're a good hitting team," Gibson said. "That's what the Reds do. It's critical to continue to make good pitches on them. They did the same thing to us yesterday, as well. Our bullpen came in and gave up three additional runs, that makes it pretty tough with that bullpen they've got down there."
Latos (11-4) allowed two runs on five hits over seven innings to pick up the win.