With injured All-Star Matt Holliday out of the lineup, Matheny slid leadoff hitter Kolten Wong to Holliday's three-hole and dubbed Carpenter the leadoff man for just the fourth time since April.
The move jump-started a St. Louis offense that scored more runs than it had in its previous five games combined, as Carpenter's 4-for-5, two-homer night paced a 14-hit game for the Cardinals and signaled the return of a hitter who has been finding his way since beginning the season on a tear from the leadoff position.
"It just shows you if you stay with it, it's going to come around," Matheny said. "But that was just a great display of everything we saw for the first part of the season."
Perhaps more than just coincidentally, Carpenter's position in the batting order on Thursday also corresponded with his early-season triumphs.
The left-handed-hitting third baseman is now 24-for-92 (.370) in 22 games when hitting first in the lineup, a figure that is juxtaposed with his 58-for-260 (.223) clip when he hits anywhere else in the order.
"I know that I was better in the one-hole to start the year, and then in the two-hole, I haven't been as good," Carpenter said. "I don't want to say that that's the reason, but it certainly seems like it. There's definitely a comfort level there -- the style of hitter I am, the approach I take in there. It seems to work out for me."
Carpenter's four runs were a career-high and the multi-home run game was the first of his career, bringing his season total to a career-high 12.
He became the first Cardinals player with four hits, two home runs, four runs and four RBIs in a game since Albert Pujols did it 2004.
"You can't say enough about Matt Carpenter," teammate Greg Garcia said. "He sparked this team tonight and it was fun to watch him do his thing."
The switch in the lineup also worked out nicely for Wong, who went 2-for-4 with an RBI.
"It's always good to change up the rotation when things aren't going right, and that's what we needed to do," Wong said. "We needed to change things around and kind of find a spark, and that's what Carp was for us tonight."
Carpenter said he takes pride in being a player who can hit from anywhere in the order. But, he admitted, the leadoff spot seems to suit him well.
"I think I bought myself another game there, at least I'm hoping," Carpenter said. "We'll see."
David Cobb is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.