Fights between two fighters that had previously sparred together?

That is what I came in to say. These guys start seeing one another at amateur tournaments when they are 11 or 12. Over the years they spar, or fight, as amateurs. Once you turn pro, guys in the same weight class will congregate to an area to get good sparring that they don't have to pay for. There have been runs, across various weight classes, at the Wild Card, Ronnie Shield's gym in Houston, and so on.

 

Hearns sparred, got Leonard ready for Mayweather SR

 

That was in Ireland, Ali was tracing his heritage or something and needed an opponent he could beat.

 

I'd imagine McCrory and McCallum sparred a bit.

 

Good one.

 

Holmes-Shavers. Which must have made the leadup to that fight interesting. Both men and their teams would have known the score. Larry would have known he absolutely cannot get clocked good by Shavers or it might be over. Earnie would have known he'd need a KO to win.

Holmes worked for Shavers in his camp for Ali. So I assume Holmes would have been one of the main sparring partners, probably sent in to legitimately try to win rounds, to give Earnie practice with trying to deal with an Ali-type slickster. My point -- they had plenty of real rounds before their fight.