Two wins stand out for me. Vitali and Grant for two different reasons. Vitali is his best win IMO. Very few fighters in history beat their heir...
Jack Dempsey was the first name that sprang to mind. He flew out of the traps and these two were both notorious as slow starters.
He's in there on my list. #10. My list is subject to change though and he hasn't always been in there. I think in any top 10 you are going to find...