Just like that, mom and dad's 600-mile drive was worth it.
"We would have walked this far to see him do that," Rick Carpenter told a national television audience.
Rick spoke later with MLB.com in a quiet tunnel off the Cardinals' family room, where other moms and dads were waiting out a rain delay that began in the seventh inning with St. Louis still leading, 3-1.
The buzz had not worn off.
"I'm just here to support him and hope he gets a pinch-hit late in the game, because that's his role right now," the elder Carpenter said. "I didn't even see him go out there. I heard the announcer say, 'Now playing right field, Matt Carpenter.' I go, 'Whoa!'
"I started texting people who were watching on TV to find out what happened to Beltran. It was quite a surprise. I went from being nice and relaxed, watching a baseball game, to -- bam! -- being instantly tense."
And when his son stepped to the plate against Giants ace Matt Cain?
"It's really hard to describe," Rick Carpenter said. "Your heart's pounding. Your blood's pumping. It's indescribable."
His boy had just as hard a time describing the moment when the baseball cleared the right-field fence.
"I couldn't believe it," Matt Carpenter said.
When he connected with that two-strike slider, Carpenter improved to 5-for-5 lifetime against Cain -- a run of success he had an even harder time explaining. The Giants righty finally won the battle in the sixth inning, retiring Carpenter on a comebacker.
"He's a really good pitcher, obviously," said Matt Carpenter. "I've had some success, but I just go out there and try to battle, get a good pitch to hit. Today, I was fortunate enough to get one of those."
In the seventh inning, the rains came, delaying the postgame reunion between father and son. They have enjoyed hundreds of postgames over the years, some with Matt as the player and dad as the coach at Lawrence E. Elkins High School near Houston.
Dad later moved to Prosper High School, a big-time program north of Dallas where he and Matt resumed the coach-player relationship last winter. Matt had gotten a seven-game taste of the Major Leagues with the Cards in 2011, but he saw his primary position, third base, blocked by postseason hero David Freese, and his second-best position, first base, by either Albert Pujols or Allen Craig.
So Matt Carpenter went back to school and learned to be a utility man. Throughout the winter, he would meet his dad and younger brother, Tyler, a former New York Mets farmhand, at Prosper High. Rick would pitch, Tyler would hit and Matt would chase down fly balls in the outfield.
"He was a workaholic," Rick said.
The work paid off. Carpenter impressed the Cardinals enough in Spring Training to make the Opening Day roster, and he batted .294 with six home runs and 46 RBIs in 296 regular-season at-bats, helping the team overcome injuries to Beltran and Lance Berkman. Carpenter played 44 games at first base, 33 at third, 10 in right field, three in left and two at second base.
Once, in late September, Carpenter found out with two outs in the top of the first inning that Freese had rolled his ankle in batting practice and Carpenter would have to start at third base. Carpenter contributed two hits and a walk in that 6-1 Cards win over the Astros.
None of his 2012 hits were bigger than Wednesday's.
"I was happy for him. It's not unexpected," said Freese. "This guy gets put into so many different positions, so many different spots in the lineup, and he just produces. I guess right now, he's just on the wrong team. This guy could be starting for so many different teams in the league."
But Rick Carpenter said his son embraced the utility role this season.
"His agent [Bryan Cahill, another of Rick Carpenter's former players] does a great job at helping Matt with it. His quote is, 'Embrace your task at hand,'" Rick said.
"He's always been a team guy," Rick Carpenter said. "When your dad is the coach, you learn in your heart about 'team.' He's always been like that. He'd like to play every day -- everybody would. But he's loving being part of this team."
Father and son will have a few days together this week in St. Louis, where the series continues with Game 4 on Thursday and Game 5 on Friday.
"My dad was really the guy who taught me everything I know about baseball, from the time I was a little kid," Matt Carpenter said. "He does all those things that a dad would do, and he's a mentor, a coach, whatever you want to call it. The impact that he's had on my abilities is second to none."