ST. LOUIS -- When Jake Arrieta and Matt Carpenter were teammates at TCU, they created their own decathlon, including events such as ping pong, foosball and basketball. Since the Cubs acquired Arrieta in July 2013, the two have found themselves going head to head in the National League Central.

Carpenter said he could cheer for Arrieta when he was with the Orioles, but since the right-hander joined the Cubs, it's been tough.

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"I wanted him to do well, but now he's done plenty well and I'm perfectly fine not rooting for him anymore," Carpenter said of Arrieta, who was a groomsman at his wedding. "But it was hard, at first, facing him because I was like, 'Man, I want this guy to do well. I want him to have a successful time here in Chicago.' That was also when they had no chance of making the postseason. But now that things have changed, I can't root for him anymore."

Things have changed. Carpenter won't have to face his TCU teammate in the first game; Arrieta got the Cubs to the NLDS with a 4-0 complete-game victory in the Wild Card Game presented by Budweiser on Wednesday over the Pirates.

The collegiate bond is strong. Arrieta and Carpenter, both 29, stay in touch with some of their TCU teammates.

"They always reach out, whether it's to Carpenter or myself, we both see [text messages]," Arrieta said. "I feel we motivate each other. It's just that chemistry we have that has carried over to our professional careers that we've had forever."

Video: Carpenter on NLDS rival and college teammate Arrieta

What about Carpenter saying he won't cheer for Arrieta anymore?

"He's lying," Arrieta said. "He roots for me. I root for him, but, obviously, I don't root for him when I'm pitching against him, because I think he's like 0-for-18 against me, which he doesn't like to talk about. It's one of those things, man. I told him, 'Hey, when you step in the box, I can't give up a hit to you.' I still haven't. I'm going to hold that one over his head for a little while longer."

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Carpenter actually is 0-for-16 against Arrieta, with five walks and has struck out four times. The Cardinals' third baseman said Arrieta's cutter is the difference maker.

"His ability to throw that at 91 [mph], 92 [mph] and then 95 [mph] with his sinker -- it's just really hard to do that," Carpenter said. "You don't know what side he's going with. You can't sit on one. If you sit on one, he goes to the other. It's not a very comfortable at-bat for lefties or righties."

Arrieta and Carpenter were teammates for two seasons at TCU, then the infielder needed Tommy John surgery and stayed a fifth year.

"What a player those guys got in the 13th round," Arrieta said of the Cardinals.

The Cubs' ace became committed to healthy eating in college, and Carpenter said he learned from the right-hander.

"Ever since I've known the guy, he's been a workout fanatic," Carpenter said. "He was healthy and conscious of his eating when we were in college, and I didn't even know what it was like to eat healthy."

The two trained together, but Carpenter couldn't quite keep up with Arrieta.

"He's big and strong, but also the most flexible human being ever," Carpenter said. "He does pilates and does stretches that are very weird. You just have to see it. He's extremely flexible. It's crazy. He had to work on that. He didn't use to be like that. He's always been big and strong and fit, but he's added this flexibility thing and it's worked for him."

Arrieta said he started exploring different workout options to prevent injuries and strengthen his body. He's carried that over to the Cubs. There's now a pilates machine at Wrigley Field.

Back to the friendly decathlon. The two most likely challenged each other in everything, from brushing their teeth to sprints on the track.

"Racquetball, pool, ping pong, foosball -- we'd go to the 'rec' after practice and stay there for four hours playing basketball against each other, running around the track," Arrieta said. "We'd have an athletic decathlon, and have 10 events and see where we ended up at the end."

Who won?

"He was good at pool, horrible at ping pong, pretty good foosball player," Arrieta said of Carpenter. "He had me in a couple events, but in the real athletic events, I had the upper hand, obviously. That's just the kind of people we are and that's why he's accelerated his career so quickly.

"I think he surprised a lot of people at first, but I wasn't one of them," Arrieta said. "I knew that's the kind of player he would be. The way he dedicated himself to his diet, his training, keeping his body in good shape and doing the things that are necessary to prolong one's career and stay injury free -- he's on board with all that. Those are the kind of people I gravitate to and that's why we've had such a great relationship. Although we compete against each other at the highest level in the same division, we still pull for each other."

Carpenter still lives in Fort Worth, Texas, while Arrieta is in Austin. They get together in the offseason. They'll have plenty to talk about this winter.

"I think in Baltimore, he talked about how they had kind of a cookie-cutter technique with him," Carpenter said of Arrieta. "He's a very coachable guy, so he tried to play along and it didn't work for him. When he came to Chicago and started over in a new scene, he could be himself. It's worked."

When Carpenter and Arrieta got together this past offseason, the Cubs pitcher was coming off a 10-5 record and 2.53 ERA in 2014.

"I asked him last year, 'Do you think you can repeat what you did?'" Carpenter said. "He was like, 'No, I'll be better than that.' And here he is."