The former Georgia Tech standout is now 16-for-16 in stolen bases in his career, including an 11-for-11 mark this season.
Trailing, 1-0, Greene entered the game as a pinch-runner after Matt Holliday delivered a clutch single. With a great jump, Greene easily beat the throw to second from catcher Geovany Soto. The ball deflected off Greene's back and into the short left field. He promptly jumped up and scampered to third.
The theft brought the crowd to its feet and was a crucial component of an improbable comeback.
"I had the green light," said Greene. "[Carlos] Marmol throws a lot of sliders, so I was trying to feel him out, see if I could get a slider to get a little half-second [advantage].
I was just trying to be as aggressive as possible."
Marmol struck out Freese but walked the next three hitters -- Yadier Molina, Skip Schumaker and Ryan Theriot -- to force in Greene with the tying run. Adron Chambers, who was running in place of Molina, zipped home when Marmol uncorked a wild pitch, giving the Cardinals a walk-off win.
Greene's steal may have been the biggest play of the game.
"He's got that ability," St. Louis manager Tony La Russa said. "Great jump, great acceleration. Big steal."
Greene had appeared in only seven games with just two at-bats since being recalled from Triple-A Memphis on Sept. 6.
But he was prepared when the opportunity came.
"It's time to stay ready, stay fresh at all times," he said. "That's what I've been trying to do. I almost pretend that I'm playing every day just to keep that mentality and be ready to go."
Greene, who is hitting .212 in 57 games this season, never thought about the negative consequences when he took off from first base.
"You can't play scared," he said. "I felt good about the situation and I was confident in what I was doing."