HOUSTON -- Aaron Harang wasn't too worried that it took six tries for him to get his 14th win.
He knew it would come sooner or later.
Harang (14-11) allowed eight hits and three runs in 7 2/3 innings, striking out five without a walk. It was his team-high 33rd start and his first win since Aug. 20.
"This late in the season you're not going to be as sharp as you were in April and May," said Harang, who improved to 4-0 against Houston this season. "It's just the grind of September. You've got to find a way to get it done. I know if I'm in there seven or eight innings every night I'm doing the job."
Denorfia hit his first homer of the season, and second of his career, in the second inning to give the Reds a 2-1 lead.
"I didn't think it was out," Denorfia said. "I think it maybe cleared it by three inches, but that's enough."
Freel extended the lead to 4-1 with his double in the fifth and Adam Dunn then drove him in with a single.
David Weathers got the last four outs for his 11th save.
Reds manager Jerry Narron was happy with Harang's performance.
"It was really big for Aaron to pitch as well as he did," Narron said. "It's taken him a while to get to 14. But he's had a great year no matter what."
The Reds improved to 10-4 against the Astros, marking the first time since 1995 they have won 10 games against Houston.
Luke Scott had three RBI for the Astros.
With a runner on in the bottom of the first, Scott hit a ball into the gap in left-center that Reds center fielder Freel couldn't come up with. Freel threw the ball toward the infield and it took a bad hop before it struck second baseman Brandon Phillips in the left eye.
Phillips fell to the ground on his hands and knees after he was hit standing in the infield near second base, staying there for a couple of minutes. He then sat down on the field while trainers attended to him.
Narron said that "everything was hazy" for Phillips when he left the game. He was taken to a hospital where an optic CT scan was normal as was an eye test. He is listed as day-to-day.
Scott added a solo homer in the sixth inning and a run-scoring double in the eighth that made it 5-4.
Astros rookie Matt Albers (0-2) started in place of Andy Pettitte, who was a late scratch so he could be with his ailing father. In just his second start, Albers allowed six hits and five runs in 4 2/3 innings. He learned that he would pitch in the middle of batting practice.
"I didn't have time to get nervous," he said.
Houston manager Phil Garner thought Albers "did pretty good."
"I think maybe he made two pitches that kind of hurt him that looked like they were mistakes," he said.
Houston's Adam Everett homered in the fifth.
Pettitte is scheduled to start on Thursday and Roger Clemens' last home start of the season remains set for Wednesday. ... Harang extended his streak of games with three or less walks to 78. ... Reds C Jason LaRue extended his season-high hitting streak to six games with a single in the fifth. ... Astros 1B Lance Berkman walked in the eighth, his 679th to move past Joe Morgan for fifth place on the Astros all-time list.