Bernard Hopkins talked up the development of Saul 'Canelo' Alvarez, insisting the Mexican boxer is still getting better.
Canelo takes on countryman Julio Cesar Chavez Jr in Nevada on Saturday, looking to improve on a 48-1-1 record.
His first and only defeat came by majority decision in September 2013 at the hands of Floyd Mayweather Jr.
Hopkins believes the way Canelo, the WBO light middleweight champion, has responded since that loss deserves plaudits.
"I've been very impressed in the development of Canelo," the American former middleweight and light heavyweight champion told Omnisport.
"I go back to the Mayweather fight. Yeah, he lost, but he gained an education, he gained from being in high school to graduating out of college.
"And that's what you see, the build-up from that fight to now, he's gotten better and better and you can't see that with all generations of fighters. They lose a fight like that, they're young, they're undefeated, their feelings get hurt because they got schooled, they didn't win a round.
"A lot of guys, they're never the same, because their heart is broken. They've been told you're gonna be this, you're great and then they get schooled by a genius in boxing.
"Canelo didn't do that, he got better and better and better."
Chavez, 31, is 50-2-1 throughout his career, and his size could prove problematic for his well-fancied opponent.
Hopkins feels the bout is an opportunity for both fighters, particularly Canelo.
He said: "It's an opportunity for Chavez Jr but it's also a bigger opportunity for Canelo.
"Why? Because Canelo's got a chance to fight a guy who's taller, who's going to come in bigger.
"This is not a concern to us. This is something he is going to take big advantage of. This is something he can expose."