Carpenter won his second straight start on Tuesday against Philadelphia, as he held the Phillies to a run and five hits in eight innings to run his record to 11-3 on the year, while lowering his earned run average to 3.05.
"I had good command of my sinker-ball near the bottom of the strike zone," said Carpenter of his dominant outing. "I also threw some good curveballs and kept them off- balanced."
Carpenter, who has allowed just two earned runs in his last two starts spanning 16 innings, beat the Cubs the last time he faced them and is 10-3 lifetime against them with a 2.73 ERA in 18 starts.
The Cubs made it two straight over the Cards on Saturday, as Tyler Colvin and Starlin Castro homered to support six solid innings from Tom Gorzelanny, as Chicago eked out a 6-5 win.
Castro finished with three hits, two runs scored and two runs batted in, while Colvin scored twice and walked for Chicago, which has won the first two games over their rivals to claim its first series against a division foe in 11 tries.
A win on Sunday would give the Cubs their first home sweep of the Cards since turning the trick in a four-game set from July 27-30, 2006. Chicago also had a three-game sweep at home over the Cards earlier in that season.
Gorzelanny (6-5) earned the win after allowing three runs on seven hits while walking three and fanning three for Chicago, which has claimed a series over a division foe for the first time in 11 tries. Carlos Marmol set down the Redbirds in the ninth to record his 18th save.
Blake Hawksworth (4-6) suffered the loss after allowing six runs -- five earned -- on seven hits over 4 1/3 innings while walking three and fanning four for the Cardinals, who have dropped three straight.
"The amount of pitches I'm throwing is just too many," said Hawksworth. "I'm just not locating the ball, especially my fastball. I'm falling behind guys and just throwing too many pitches. That's the factor right now, it's not the home runs, just my location is off."
Chicago, meanwhile, will pin its hopes tonight on righty Ryan Dempster, who is 8-7 with a 3.70 ERA. Dempster is unbeaten in his last three starts, but did not get a decision on Tuesday against Houston, which managed seven runs (four earned) and eight hits in five innings of his team's 14-7 win.
Dempster was hit hard by the Cards back on May 30 for six runs in 6 2/3 innings and is 6-7 in 42 games against them with a 4.55 ERA.
St. Louis took two of three from the Cubs earlier in the season at Wrigley.