Eric Morel and Abner Mares will take contrasting plans into their WBC title fight on April 21.
Morel has adopted a now-or-never attitude in his bid to become a world champion for the first time in more than eight years. Unbeaten Mares wants to make sure never happens.
The two former champions meet at El Paso, Texas, for the WBC super-bantamweight title vacated by Japan's Toshiaki Nishioka after he failed to land a fight with Filipino star Nonito Donaire.
"If he wants to come back and try to win back the title, I'm ready to fight him," Mares said on Friday.
Morel, from Puerto Rico, has built up a record of 46-2, with 23 knockouts. He has won 11 fights in a row since losing to Martin Castillo of Mexico in 2005 after losing the same title in 2003.
At 36, Morel knows he cannot afford another setback in his bid to return to the throne.
"My preparation for this fight has been the best. Basically this is it," he said. "It's do or die for me.
"Age is not catching up with me; 36 is nothing but a number. I'm in great shape. My feet are still there. My speed is just tremendous. I still have great power. I feel like nothing is going to stop me."
Mares, 26, has not lost in 23 fights. He drew once and won 13 by knockout.
"I can't wait to become a world champion in my second weight class," Mares said. "I'm not training any differently because he's 36. I'm not looking at numbers. It's another opponent, another fight, and I have to train my best.
"I expect a tough fight. I know what I'm getting myself into. It's a big step-up fight for him. He's basically trying to make a comeback. He's going to fight hard. But I train hard too and I'm ready for him."
Panama's Anselmo Moreno, who stands at 32-2, with one drawn and 11 knockouts, will defend his WBA bantamweight crown against Mexico's David de la Mora (24-1, 17) on the same card.
Moreno, a southpaw who has won 26 fights in a row over the past 9 years, will make his tenth defence of the belt he won in 2008.