Fights in which the WINNER lost everything he or she had left

Imagine if Brit bodybuilder Bruno had been one punched in the opening round by American bodybuilder Jumbo Cummings! Frank barely kept his feet but had no idea where he was. If he'd fallen, he'd have never beaten the count. Does he even get on his "first" legs after that? (He has repeatedly admitted in retirement that Jumbo's round ending right was by far the hardest single punch he ever was hit by. In his final bout, Joe Frazier showed his chin by taking a number of those over ten full rounds.)

How does the Brit bodybuilder's career proceed if:

Jumbo Cummings KO 1 3:09 Frank Bruno