Donny LaLonde is the guy Sugar Ray Leonard beat for his light-heavyweight title. LaLonde beat nobody of note except for middleweight contender Mustafa Hamsho and light heavyweight contender Eddie Davis. After Leonard beat him he retired for three years, moved to Cruiserweight and never entered the top ten rankings again. Sergey Kovalev is the guy that Canelo Alvarez beat for his light-heavyweight title. Kovalev beat an ancient Bernard Hopkins, Jean Pascal twice, and unofficially beat Andre Ward at least once. He held three titles, and regained one twice. He is a hall of fame level boxer who was in the pound four pound lists for a couple of years. After Canelo beat him he should retire and never fight again. Kovalev's career is much more impressive than LaLonde's but 1988 LaLonde beats 2019 Kovalev.