1. Hearns 2. Minter 3. Sibson 4. Monroe 2 5. Lee Clearly Hearns was his greatest win, the title win over Minter in front of a hostile crowd was a brilliant performance and Sibson was his most complete performance against a guy people thought might be a threat to him. Now, the Monroe rematch is not available to watch but after the one comprehensive and uncontroversial defeat of his career, he came back and battered The Worm in a war, showing the determination that propelled him to such a long and dominant title reign. The Lee fight shows what he could do against guys who were worthy enough title challengers but not on his level - 67 seconds was all it took - and reflects what made Hagler's reign special. It was the dominance of his performances more than the opposition that was so impressive.
I reckon that win likely would have slipped Hagler into the bottom of the 10 but i'm not sure he would have been a majority top 5. It's possible, sure. Both Hagler and Monroe himself were unranked at the time of their rematch. In the 13 months between bouts David Love had stopped Monroe in 4 rounds which put him in the top 6 and outed Monroe from the 10. It's a loss Hagler needed to address tho. Interestingly Love also beat Briscoe right after Hagler did and stopped Bobby Watts as well.
I've seen the Colbert fight and the second Monroe fight. Willy resembled a broken wall that had a run in with the wrecking ball and the victory over Colbert was impressive. The way he boxed Mike wasnt but the way he went after him in the last round, then destroyed him in mere seconds. Mike got on his bike, circled one way, then the other but at that time, Marvin was inescapable as he caught Mike with the left and it was this win that vaulted him to the top of Ring's middleweight rankings. never before seen in the top 10, there he was at the top spot in January 78 where he would reside for the next 3 years. Most impressive? The first Hamsho fight