Give it to him against Cincinnati and the game's usually over.
Hunter Pence hit a three-run homer to give the Astros an early advantage, and Oswalt locked down the Reds in a 7-4 victory Thursday night that made him 21-1 in his career against them.
"That's the way we always feel about Roy," said first baseman Lance Berkman, who had a pair of doubles among his three hits. "He's been our ace for a while. It's always a good feeling when he's pitching, especially against Cincinnati. He's had success against them. The numbers say that."
Carlos Lee went 3-for-3 and drove in two runs and Miguel Tejada also had three hits while Oswalt was shutting down the Reds over seven innings, his longest outing in three starts since coming off the disabled list on July 28.
Oswalt (9-8), who has won each of his last six starts against Cincinnati, escaped a bases-loaded jam in the first inning and didn't allow a run until the seventh. He gave up nine hits with two walks and five strikeouts.
"He had a nice outing," Houston manager Cecil Cooper said. "I thought about letting him go deeper, but the seventh was a little stressful."
The Reds have lost three straight and six of seven.
"We had some opportunities," manager Dusty Baker said. "We had quite few chances."
Houston took a 1-0 lead in the first when Tejada doubled with one out and scored on Lee's two-out single to left.
Kaz Matsui led off the third with another single and, after moving up on Berkman's single, scored on Lee's grounder through the hole into left field. Pence followed by driving Josh Fogg's 2-0 pitch into the seats in left-center for his 15th homer of the season.
"That three-run homer by Pence was the difference in the game," Baker said. "It's tough to keep getting behind like that, especially when the guy over there is a pretty tough pitcher. It's tough to play catch-up consistently, and when he gets ahead like that, he can relax and throw whatever he wants at any time in the count."
The Astros made it 6-0 in the fifth when Berkman hit a leadoff double and Lee walked, ending Fogg's night. Pence pushed Berkman to third with a fielder's choice grounder, and Ty Wigginton hit a sacrifice fly that center fielder Corey Patterson appeared to save from going over the fence with a leaping catch.
Fogg (2-4) allowed eight hits and six runs with in four innings.
The Reds loaded the bases against Oswalt with two outs in the first, but Oswalt struck out Edwin Encarnacion on three pitches -- a foul tip and two called strikes.
"I felt pretty good," the right-hander said. "I got out of the first inning and cruised after that. I threw a lot of pitches in the first, but after we scored a few runs, it seemed like they started swinging early in the count and giving up at-bats."
The Reds broke up Oswalt's shutout in the seventh on pinch-hitter Jolbert Cabrera's two-out walk and singles by Jeff Keppinger and Joey Votto. Encarnacion added his 21st homer, a two-run shot to left-center off left-handed reliever Wesley Wright in the eighth.
Tejada scored on Wigginton's bases-loaded sacrifice fly in the ninth. Brandon Phillips tripled with two outs and scored on a wild pitch in the bottom of the inning.
Reds RF Jay Bruce led off the sixth with a double to extend his hitting streak to 11 games, one short of the season-high streak the rookie put together July 9-23. ... Cincinnati CF Jerry Hairston Jr., who has one pinch-hit appearance since Friday after aggravating a hamstring injury that left him on the disabled list for the second half of July, ran the bases at full speed before Thursday's game. "If it was up to me, I'd be in there, but once I'm back, I want to be back for the duration," Hairston said. ... Houston CF Michael Bourn started after missing the last 10 starts with a sprained right ankle.