"It was kind of what was working tonight, so we ran with it," Bettis said. "Once they made an adjustment, we tried to stay ahead of them."
The outing was a forward stride for Bettis (4-2), who in three of his previous four outings had key mistakes prevent him from earning wins.
On Tuesday, he breezed through the sixth. He was clipped for three singles and the only run, on Randal Grichuk's single, after recording two outs in the seventh. So reliever Boone Logan forced a Carpenter grounder to escape. The Rockies' four shutouts through 38 games match last year's 162-game total, and they flirted with another, but Logan, Carlos Estevez and Jake McGee (13th save) helped the Rockies improve to 12-8 on the road.
For Bettis it was another step toward his goal of being a starter his team can depend on to pitch deep in games.
"That's the goal every time," Bettis said. "I wanted to work off the first six innings I took from the last start. I felt like I am progressing the right way."
Bettis is part of a staff-wide positive progression. Rockies starters have a 3.21 ERA in their last 12 road starts, and Bettis has had four quality starts in his six road assignments.
Rockies catcher Dustin Garneau clued in with Bettis' comfort with his two-seam and four-seam fastball -- which stayed 90-93 mph, with enough movement and sink to be hard to track.
"His sinker was really, really on tonight," Garneau said.
Bettis held the Cards hitless until Jeremy Hazelbarker's infield single in the fifth and faced two on with one out before forcing a pair of fly balls -- a dangerous one from pinch-hitter Brandon Moss and a lazy one from Carpenter.
"That was the inning I had to grind through," Bettis said. "My command was starting to waver. I knew I had to get out of is somehow without major damage done."
The Cardinals entered leading the National League in slugging, barely ahead of the Rockies. Manager Walt Weiss wants his pitchers challenging the Cards in the strike zone. Bettis set a tone.
"That's what we want to do against everybody," Weiss said. "Attack with all our weapons, and that's exactly what Chad did."