Briscoe should have beaten Monzon in their first fight yes, but Monzon had not reached his peak. Monzon outclassed Bennie in their rematch for the title, a one-sided win. For this though, I pick Briscoe, probably stopping The Blade.
Briscoe was 1 year younger than Monzon . If Monzon had not reached his peak then Briscoe was even further from his .
This is a big exaggeration . Briscoe was no Nigel Benn . And Barkley was severely weakened & drained in his losses 2 Benn , Duran , Toney and probably Sims , Nunn & Kalambay as well . Not that I consider d Kalambay & Nunn fights losses . More generally , Barkley did not fit 160 , but it did pay off 4 him vs Hearns . But maybe it weakened him in d following years , he even was drained vs Toney @ 168 , a few moths after it he fought at HW weighing like a HW . So because of Barkley being weak @ 160 Briscoe might have beaten him , but no way @ less than 7 rounds .