Rios, the former champion, had been slated to take on Yuriorkis Gamboa, but will now takes on Cuban-born fighter Abril on Saturday.

Fireworks have marked the build-up to the bout, including a shoving match at a Los Angeles press conference last week and Rios believes his opponent will be going down "real hard".

"No unheard-of fighter like Abril will ever beat me," Rios, who is undefeated in 30 bouts, declared.

"He's going to go down and he's going to go down real hard. In the boxing world, Abril is in the darkness and I will keep him there."

Nutrition

Rios insists he is taking his training more seriously now and has even hired a nutritionist - a move he believes has paid off.

"He is helping a lot," Rios said. "He is cooking great and I'm eating great.

"This is the smartest move I have made in my career. And it's paying off very well right now."

Abril gained the interim title after defeating former champion Miguel Acosta in October and brings a record of 17-2-1 with eight knockouts to the contest.

"I feel very good and I am very prepared for this fight," Abril commented. "You have been talking a lot of smack. Well, I'm here and not afraid of you."