Pettitte has won four consecutive starts since returning from the disabled list on April 29. The left-hander had missed 19 games with a strained left elbow after losing his first start for Houston on April 6 against San Francisco.
The 31-year-old Pettitte has compiled a 2.35 ERA during his winning streak, which includes a 7-4 victory over the New York Mets on Saturday. He allowed four runs and six hits over six innings, and tied his season high with eight strikeouts while walking one.
Pettitte, who spent nine seasons with the Yankees before signing with the Astros in the offseason, won a career-high eight straight decisions with New York from June 14-July 29 last season.
“He’s a big-game pitcher,” Astros shortshop Adam Everett said of Pettitte. “He’s won a lot of playoff games. Shoot, he’s won over 150 regular season games. You’re talking about a guy that knows how to go out there and pitch and knows how to win.”
The Astros failed to complete a sweep of the defending World Series champion Florida Marlins on Thursday, losing 6-2.
Lance Berkman hit his third homer in as many nights for Houston.
“We were focused on winning two of three here,” Astros center fielder Craig Biggio said. “It’s hard to sweep a good team on the road, so we’ll take this (series) win and move on.”
The Reds have won five of six, including Thursday’s 3-1 victory over Colorado.
Danny Graves pitched a perfect ninth to become the Cincinnati Reds’ all-time saves leader. He moved past John Franco with his 149th career save, and major league-leading 18th in 22 opportunities this season.