Chris Cariaso couldn’t believe he was getting the opportunity of a lifetime when the UFC phoned him recently.

Cariaso, a veteran of the sport, will challenge flyweight champion Demetrious Johnson for the title at UFC 177 in the co-main event next month.

“I was in just as much shock as everybody else,” said Cariaso, during a recent interview on Radio. “I had to hang up the phone to call them back. I had to go around the house real quick to calm down.

“It was an ecstatic feeling.”

Despite riding a three-fight win streak, most didn’t view Cariaso (17-5) as a viable challenger to Johnson’s title. But, with other top contenders either booked or injured, the 33-year-old moved to the front of the line.

“Getting this call, I’m not even listening to what anyone else is saying,” Cariaso said. “I’m focused on my training to go in there and be the best I can be. You can say what you want to say now, but I come to fight.”

Cariaso hasn’t lost since a 2013 decision defeat to Jussier Formiga. He moved down to flyweight in 2012, defeating Josh Ferguson. His only other loss in the division came to another contender, John Moraga, vua submission to close out 2012.

While the betting odds will be heavy for “Might Mouse,” many others have proven them wrong before. Chris Weidman upset Anderson Silva to become the middleweight champion and T.J. Dillashaw stunned Renan Barao to win the bantamweight gold.

“Anything can happen,” Cariaso said. “I’ve been doing this since I was five-years-old. I’m ready.

“It’s a dream for me to be out there, so I’m ready to go out there and capitalize on this.”