Carpenter hit a bases-loaded sacrifice fly in the 10th inning to give the Cardinals to a 2-1 victory over the Cincinnati Reds on Tuesday night.
David Freese walked to lead off the inning off Sam LeCure (0-1). Tyler Greene came in as a pinch-runner and advanced on a sacrifice by Yadier Molina, the 37th of his career. After an intentional walk, left-handed reliever Bill Bray entered and walked Daniel Descalso to load the bases.
That put the left-handed hitting Carpenter in against Bray.
"Statistically he's been pretty good against lefties his whole career, as short a career as it's been," Matheny said. "I liked our odds with him making something happen."
Carpenter, who returned to the bench after playing the last four games for the injured Lance Berkman, made Matheny's move pay off.
He worked the count full before flying out to right field. Jay Bruce's throw home was unable to nab Greene. It was Carpenter's 11th RBI of the season.
"Bases loaded, chance to win a ballgame as a pinch-hitter, that's a situation you want to be in," Carpenter said. "I mean, my heart was pumping a little bit. As a hitter, you dream of it. It's a lot of fun, and it's lot more fun when you pull it off.
"With Tyler at third, you don't have to crush it all the way to the wall. Things are working out."
Carpenter is hitting .409 and came off a game Sunday where he had four hits and five RBIs.
"It didn't take a genius to watch a guy do what he did yesterday and realize he's pretty hot," Matheny said, "and then realizing their move is to leave the lefty in and knowing the stats and knowing he hits lefties well, it all played together pretty well."
The Cardinals scored the winning run without an official at-bat -- a walk, a sacrifice bunt, an intentional walk and a sacrifice fly.
That caught the eye of Cincinnati coach Dusty Baker.
"We're playing just good enough to lose right now," Baker said. "We just have to execute better. You practice and practice and preach and talk about things, it's just not happening."
Jason Motte (1-0) worked the 10th for St. Louis.
Cincinnati used two errors and a single for an unearned run to tie the game at 1 in the eighth. Descalso let Ryan Hanigan's grounder go through his legs at second for an error. Reliever Mitchell Boggs mishandled pinch-hitter Wilson Valdez' sacrifice, allowing pinch-runner Devin Mesoraco to reach second. Zack Cozart singled to right two outs later to score Mesoraco.
Carlos Beltran gave the Cardinals a 1-0 lead when he hit a first-inning home run into the right-field bullpen.
"It was a slider. I tried to throw a strike and it just stayed high for me," said Reds starter Johnny Cueto, who pitched seven innings, allowing seven hits. "It was my fault. I should not do that."
Beltran, who also singled and walked, contributed a defensive gem in the third inning. He cut down Drew Stubbs trying to go first to third on a single with a one-hop throw to Freese from right field. Beltran had 10 outfield assists last season.
St. Louis starter Kyle Lohse opened the game with 12 consecutive strikes, and finished with seven scoreless innings. He allowed four hits and struck out the side after a walk and a single in the fourth inning.
"I had good location," Lohse said. "It's not normal for me to strike out three guys in a row but I hit my spots. It was good to get and keep them to no runs."
Lohse, who threw 90 pitches, struck out six in dropping his ERA to 0.90 after three starts.
"It's just a shame we couldn't get him a 'W' out of that," Matheny said. "He was terrific. That's as good as you can ask for anybody."
After Cueto hit Molina to start the second inning, home plate umpire Tony Randazzo immediately warned him and both benches. Jon Jay followed with a single to center, but Cueto pitched out of the jam.
St. Louis stranded eight runners in the first four innings when Cueto threw 79 pitches.
It was the first extra-inning game of the season for St. Louis. Cincinnati is 1-3 this season in extra frames. ... Berkman returned to the St. Louis lineup after missing four games with a strained left calf and Freese was back after missing two games with a sore finger on his right hand. ... St. Louis has homered in each of the four games with Cincinnati this season with a homer coming in the first inning in three of the games. ... The Reds franchise remains two wins shy of 10,000 . ... MLB announced the draft order for the June 4 first-year player draft Tuesday. Cincinnati will select 14th in the first round while St. Louis will draft 19th and 23rd. The 19th selection if compensation for the Los Angeles Angels signing Albert Pujols. The Cardinals have five of the first 59 draft selections. ... Reds 3B Scott Rolen remains in 52nd place on the career doubles list, one behind Andre Dawson's total of 503.