October baseball was Chris Carpenter’s motivation. It was the reason he disobeyed doctors’ orders and sped up his own rehabilitation, why he welcomed the challenge of trying to accomplish something few thought he would be able to — pitch in the postseason this year.

On Wednesday, in just his fourth appearance in 2012, Carpenter delivered 52 / 3scoreless innings to help the Cardinals push the Nationals to the brink of elimination.

He typically doesn’t bask in the moment when starting a game, but on this occasion, Carpenter considered everything he went through to get to this point. From when he lost feeling in his right shoulder in spring training, to when he opted to have radical surgery — a procedure that was supposed to mark the end of his season — to repair damage to the nerves that ran down his right arm in July, to defiantly insisting he would return to the mound and pushing his recovery to make good on the promise.

“When I walked up, my first at-bat, Joe West, the umpire, said to me something about ‘what a beautiful day to play baseball,’ ” said Carpenter, 37, who earned his first win of the year Wednesday. “And I was like, ‘yeah, you know what, you’re right.’ It was a fantastic day. Great weather, crowd was amazing. This is what you play for and I was definitely — I took it in a little bit.”

Despite his lengthy resume of winning key postseason games, it was tough to gauge exactly how Carpenter would fare after throwing only 17 innings this year prior to facing the Nationals. While Carpenter may not have been in vintage form — giving up seven hits — he threw 69 of his 106 pitches for strikes and effectively worked his way out of a few jams as the Nationals stranded eight runners in the first five innings.

The key to Carpenter’s success on the mound as well as his ability to come back from a significant injury, according to his teammates, isn’t necessarily due to his innate talents as a pitcher, but his drive.

“Watching him after surgery, just rebounding from going under you could see in his eyes he really wanted to come back,” Cardinals third baseman David Freese said. “Some pitchers, I’m sure would just shake it off and get ready for next year, but that’s not Carp. He’s an animal out there.”

Carpenter’s intensity doesn’t go unnoticed by the opponents he faces either.

“He’s a competitor. And this is not disrespect to him, I don’t think any of his success is based on his stuff. It’s his heart,” Nationals shortstop Ian Desmond said. “He goes out there and competes and it’s about winning or losing, not about, ‘Is my curveball there? Is my sinker there?’ or anything like that. It’s about making good pitches and competing, and he did that today.”

For the Cardinals, now just one win away from reaching the National League Championship Series, seeing their ace triumphantly return to the postseason against all odds only helps fuel the rest of the clubhouse.

“All the time he spent in the training room, the weight room getting back to this point, you can’t help but feed off that,” centerfielder Jon Jay said. “It would have been easy for him, someone that has two rings and he’s made his money in this game to just say hey, ‘You know what, I’ll be out there next year,’ but he wanted to be out there for us and we definitely respect that.”