Alexis Arguello, Henry Armstrong, and Bernard Hopkins all lost their pro debuts.

I think the Marquez brothers did too.

Joe Louis improved on his tendency to be lazy with his jab after the Max Schmeling loss.

As far as I'm concerned, Lennox Lewis losing to Oliver McCall was a blessing in disguise. It was Manny Steward in the other corner who picked up on Lewis's poor balance and being so open when he threw the right hand. Oliver caught Lewis with that same right hand in round 1, it just wasn't as clean. Lewis fought a lot of good punchers, and I think sooner or later, he would've been caught when he made those mistakes.

Lewis's balance and overall technique became better with Steward.