It was St. Louis manager Mike Matheny's first challenge of the season.
"I could tell by Carp's reaction, and what I saw, it was close enough that we needed to take a good look at it in that situation," Matheny said. "They got the call right."
With runners on first and second in a two-run game, Daniel Descalso hit a double to center. Kirk Nieuwenhuis corralled the ball and fired to cutoff man Ruben Tejada, who whirled and threw home to Travis d'Arnaud, who tagged Carpenter fractions of a second before he touched home plate.
Though Carpenter was nearly past d'Arnaud on the basepaths, replays clearly showed that the Mets' catcher was able to turn around and touch him with his mitt.
"When the throw was coming, I saw [Carpenter] in my peripheral coming past me," d'Arnaud said. "I already started tagging behind me instead of coming wide, and fortunately, I got him before I touched the plate. I knew I tagged him, I just didn't know if he touched the plate before that."
The Mets have done well with their own replay challenges this season, winning both, but needed to sweat out Matheny's for one minute and 20 seconds.
"I was just hoping they were going to call him out," said Kyle Farnsworth, New York's pitcher at the time. "It was a perfect replay."