Based on the OP scenario, this is a very tough fight. I think it fair to consider Canelo and Mugabi well-matched, at the respective stages of their careers. I can't see Canelo exerting his will over Mugabi (as did Hagler, in the latter half of their bout). So, I'd say it goes the distance in a brutal war. Mugabi could take a decision here - on fair scorecards.
Hagler was not at his best that night. He didn't really want to fight anymore, and he had been inactive for almost a year since fighting Hearns. The Hearns fight was what he always wanted, he got the acclaim which seemed so important to him, and I think that was what he wanted. He had some injury in training and the fight was postponed from Nov. 6, 1985 ( think it was) to March 10, 1986. It was just an odd night. Sandoval had an incident and the rain and then Hearns with Shuler, where people didn't expect that. Then Hagler comes on and it is cold and Marvin to me looked soft and uninspired, and he won but he had to pore it on late. I could attribute the fight to Mugabi, but to me it was more about Hagler not being tops that night. John was strong, and for Marvin to have fought a dangerous guy like Mugabi when he was not motivated and not active was a risk, but he was a professional and he won the fight, and then Ray decides to come back knowing that Marvin would take more time off and looked off and sluggish.. Marvin looked better against Ray, but not fluid like he had against Hearns, which to me was his last championship quality fight where he was in shape and motivated and came in good. Mugabi to me didn't have enough top level fights for people to say "Marvin ruined him". Ruined him from what? We really didn't see a succession of great fights to see what he really was about. . After Hagler he got a thumb and quit against Thomas. Completely derailed against Norris. Even the Jacquot fight was tainted by the ankle.
actually the complete opposite especially here in classic. Mugabi is the overrated one, where his best performance is a loss. Canelo stops him late