Staff Sgt. Colton Smith remained unbeaten in the mixed martial arts cage since his release from the UFC, defeating Marcus Andrusia via first-round stoppage Saturday night in the main event of Rock’s Extreme Fight Night XIV in Harker Heights, Texas, a short drive from Fort Hood.

Smith, who recently re-enlisted for four years and serves as a combatives master trainer at the base, announced the results himself via Twitter.

The first-round win puts Smith at 5-4 for his career and 2-0 since leaving the UFC in 2014. Three of his four professional losses came with the promotion, all on the heels of a unanimous decision victory over Mike Ricci in December 2012 that made Smith the winner of the 16th season of “The Ultimate Fighter,” the UFC’s reality competition show.

“I’m only 27. Right now I’m hitting my stride,” Smith said in a post-fight interview posted on YouTube. “I’m not anywhere near my prime. … I was kind of getting a big head about myself [while in the UFC], and I’ve kind of refocused myself.”

Andrusia’s highest-profile fight came in 2010 with the Bellator promotion, one he lost via first-round submission. He entered Saturday’s fight with a 6-9 record, according to Sherdog.com, and gave up seven inches in height to the 6-foot Smith.

Smith’s skills, his size and the hometown crowd proved too much for Andrusia to overcome.

“I really trained hard for this fight,” Smith said in the interview. “I really wanted to kind of showcase more of my skill sets. I’m kind of glad I didn’t have to, so my next opponent’s going to be in the dark.”

Smith told Army Times in April that he plans to attend air assault school in Fort Hood in June, then head to Fort Benning, Ga., for the Senior Leader Course.