Coleman, who might be an option for the bullpen, closed the 6-1 win over the Brewers with a 1-2-3 ninth.
"It was fun," Coleman said on Sunday.
A starter most of his career, Coleman thought it might be boring sitting in the bullpen.
"But as soon as the phone rang, I was thinking, 'OK, maybe I'll be next up,' and nope, nope, nope," he said. "By the seventh or eighth inning, I thought I might have a chance to close the game because it was 2-1. It was pretty awesome."
Does his heart rate kick up each time the bullpen phone rings?
"Not any more," he said. "It's more excitement. You want to be the guy. Before, when I was the rookie and it would ring, I wasn't saying, 'Don't be me,' but at the same time, you get that nervousness. Now you want it to be you."
The Cubs are set with closer Carlos Marmol and also have setup pitcher Kerry Wood, but manager Dale Sveum is still sorting out the rest of the bullpen.
"There's a lot of bullpen spots open and guys competing," Coleman said. "I don't mind where I'm at. I can come in for one inning. As a starter I like to establish a sinker and throw different pitches. Out of the 'pen, I can hit 93, 94 [mph] if I need a good fastball.
"I've developed a new slider where I drop down a little bit, and that's a strikeout pitch. I feel [that] overall I can adapt better to the bullpen now with what I have. Last year, at the beginning of spring, I was throwing normal stuff, and I didn't think I would be effective in the bullpen. Now I'm striking out a few more guys and making pitches when I need to. I think I could adapt to that very easily."
Sveum said that Coleman has good velocity and command of his breaking balls and just needs to be consistent with his pitches.
"He's interesting," Sveum said. "He's a great athlete. He can throw strikes [and] get ahead of the count, and keeps the ball down."