The Astros know what they have in ace Roy Oswalt. But after him, their rotation is a bit shaky. Brandon Backe is coming off Tommy John surgery, Wandy Rodriguez has been inconsistent in past seasons and Woody Williams has had a terrible spring.
Chacon signed a $2 million, one-year contract with Houston last month and has said one of the selling points to playing for the Astros was a chance to compete for a starting job.
Astros manager Cecil Cooper had been noncommittal about Chacon's place in the rotation this spring, but said after the game that he had secured a spot.
"Really at this point, we'll have to say that he's got to be one of the guys," Cooper said.
The right-hander hopes his strong outing will be a boost to the pitching staff.
"We've been struggling as a staff all spring and coming out tonight and having a good outing you definitely ... feed off that," Chacon said. "Now is the time in spring where things really have to start tightening up."
Cooper said Chacon's work was very encouraging and that either he, Backe or Rodriguez need to prove to be a reliable starter for the Astros to be successful.
"We need one of those two or three guys behind Roy to step up so we can count on them," Cooper said.
Most of Houston's relievers also did well on Wednesday with new closer Jose Valverde and right-hander Doug Brocail throwing a scoreless inning apiece.
Oscar Villarreal was the exception to Houston's strong pitching night, allowing seven hits and five runs in 1 2-3 innings. Wesley Wright, who's never pitched in the majors, got the win for Houston, striking out Scott Thorman after replacing Villarreal in the eighth.
Cooper was impressed with Wright's poise and said he's playing his way into a spot on the team.
"That was probably the nicest part of the night," Cooper said of Wright. "He looked like a big leaguer tonight. The game is on the line and he goes right at him."
Braves starter Jo-Jo Reyes may have hurt his chances for winning the fifth spot in the rotation. He gave up five runs and six hits in four innings while walking four batters but said he was still encouraged after making use of lessons learned in side sessions with another left-hander, Tom Glavine, and pitching coach Roger McDowell.
"Me and Glavine and Roger have been working on some stuff in the bullpen. I was bringing it over today and making strides forward but I've got to keep working and keep it going."
Reyes said he was working on being more consistent in the way he plants his left foot during his delivery.
"I felt really good," he said. "It may have looked like I was all over the place, but when I was missing I was just missing instead of being erratic. ... We were working on making my footing be more consistent instead of different with each pitch."
New Astros shortstop Miguel Tejada went 4-for-4 with two RBIs and his first home run of the spring and Carlos Lee had two hits and a pair of RBIs.
Reggie Abercrombie grounded into a force out that scored Jose Cruz Jr. in the bottom of the eighth to give Houston the win.