The teams link up for the second game of a three-game set on Wednesday at Busch Stadium.
"We respect the game and we respect every team and every player," Matheny said. "We have our hands full. We really control what we can control. These guys need to go out and play good baseball, that's all there is to it, no matter who we're playing against. We don't want to get too high for one team. We don't want to get too low for one team or else you're going to get bit either way."
The teams will square off eight more times this season, twice in this series and then six more times Sept. 18-26. The Cardinals are 4-3 against the Astros, with the first six games taking place at Minute Maid Park.
Kyle Lohse, carrying the best winning percentage (.857) in the National League, will start for the Cardinals. He hasn't lost any of his last 10 starts.
Against the Astros in his career, Lohse has a 2.93 ERA. That's his lowest against any team except the Rays.
Earlier this season, though, Lohse took one of his two losses against Houston, allowing five runs (three earned) in five innings in a 5-4 loss.
Bud Norris' last 10 starts have gone quite differently from Lohse's. He is 0-7 in those outings, posting a 5.95 ERA. The Astros are just 1-9 in those 10 starts.
"It's been frustrating," Norris said. "I've got a lot of good ones and a lot of bad ones. Being consistent is something you're trying to get and figure out. I think I did a good job with that last year, and unfortunately there's been a couple of really bad starts this year, and I have to keep plugging away."
Norris did have some success against the Cardinals on June 6, striking out 12 in six innings, but he also allowed four runs on seven hits and took the loss. In 12 career starts against the Cards, Norris has a 2.47 ERA, his best against any opponent.
Astros: Greene returns to former ballpark
Infielder Tyler Greene, a former Cardinal, couldn't quite find the visitors' clubhouse at Busch Stadium on Tuesday.
"I never had to go past the home clubhouse in the hallway there," Greene said. "A little lost at first. I had no idea exactly where it was."
Greene has enjoyed a chance to get regular at-bats with the Astros. He is batting .324 with two homers and four RBIs in his first 10 games with the team.
"It's been a big breath of fresh air for me," Greene said. "I'm excited about the new start."
Cardinals: Beltran dealing with sore left hand
Center fielder Carlos Beltran, dealing with a sore left hand, didn't play Tuesday against the Astros.
Matheny said Beltran's hand has "been bothering him for a while now." Beltran wasn't in the lineup Saturday, either, but Matheny said that was just to get him some rest.
Jon Jay started in center field, with Allen Craig in right field and Matt Carpenter getting the nod at first base.
Beltran, who is day to day, is 4-for-23 with two RBIs in the first seven games of the homestand. He is batting .237 since the All-Star break.