SAN JOSE, Calif. – For a guy who made a successful UFC debut, kept his perfect record intact and defeated a former champion, Daniel Cormier was awfully bearish about his first trip to the octagon.

Cormier (12-0 MMA, 1-0 UFC), Strikeforce’s recent heavyweight grand prix winner, scored a shutout unanimous-decision victory over Frank Mir (16-7 MMA, 14-7 UFC) in the co-main event of UFC on FOX 7. The bout took place Saturday at HP Pavilion in San Jose, Calif., and aired on FOX.

Cormier, an Olympic wrestler who relied heavily on his clinch game and close-quarters fighting, admits the bright lights of the UFC got to him.

“I’ve had a very long athletic career, and I’ve competed at the highest levels of all my sports,” he told MMAjunkie.com (www.mmajunkie.com) after the fight. “I always kind of laughed at (UFC President) Dana (White) when he said there were jitters and nerves that come with this.

“… But man, I was nervous. I felt so nervous. It’s almost like you want it so bad and you want to do so well, and then you just kind of lay an egg a little bit. I didn’t fight the fight I wanted to.”

Cormier earned a victory via 30-27 scores. The win followed some impressive recent performances over the likes of notable Josh Barnett, upcoming UFC title challenger Antonio “Bigfoot” Silva and veteran Dion Staring.

But against Mir, Cormier said the mental effects of his UFC debut may have morphed into physical issues.

“More than anything, I felt tired, and I’ve never gotten tired,” he said. “Usually I’m in a fight, and I feel great. I can go long. But in this fight, for some reason, I was tired, and I think it was my nerves. I was very nervous in the back.

“I felt like my legs were kind of weird. But I went in there and fought, and I fought as well as I could. It wasn’t ideal, but if you can feel bad and beat a guy who’s a two-time champion, there’s got to be some positives in that.”

Prior to the bout, Cormier – despite a near-tragic weight cut during his wrestling days – discussed a possible move down to light heavyweight. With teammate Cain Velasquez holding the UFC heavyweight title, and with Cormier already a bit undersized for the division, it’s something he’s long considered.

He said it’s still a possibility, and he doesn’t think his latest performance necessarily will impact the decision either way. But ultimately, numerous people will weigh in.

“It’s really going to be a team decision,” he said. “We need to get together with the UFC and the management team and everyone else and figure out what the next step is. Me personally, even if they said you’re going to fight Cain Velasquez next, I don’t think tonight’s performance warranted a title shot.”

If he opts against it, Cormier hopes to fight another heavyweight as soon as possible. But if he does make the drop, he said it could mean a lengthy layoff as he assures he trims the pounds safely.

“I want to do it healthy,” he said. “I don’t want to die.”

For complete coverage of UFC on FOX 7, stay tuned to the UFC Events section of the site.