how could Floyd ko Ortiz with only one punch ?

Because Ortiz quit, quite clearly

I assume he thought he'd be DQ'd for the headbutt because it certainly wasn't even half-subtle

Having said that he was caught by surprise with the punches but he probably just wanted a way out

If 6 back & forth rounds with Marcos Maidana are enough to make him quit it's fair enough to assume 4 pretty one-sided ones with Mayweather are

 

He got sucker punched

 

He got up from a much bigger shot from a bigger puncher in Berto.

Against Mayweather he just quit.... Again.

And then stood there laughing like a fool when Merchant was questioning him.

 

OP loses all creditability if he can't see the clear difference from a punch you are ready for in the middle of a round.. and a punch just standing there relaxed and limp.

Compare it if you will.. to football.. What do you think would be worse? Being tackled.. aware that it is possible for you to be tackled during that moment and somewhat be physically and mentally ready for it... Or just standing there flat-footed while someone lowers the shoulder and splits you in half?

 

This

 

They also lose crediblity for saying one punch, when it was clearly a two-piece special, extra crispy.

 

floyd hit him when he wasnt looking. there the punches that knock you out. the ones you dont see.

 

The foolishness begins....

 

Berto a PED user couldn't K.O. Ortiz but Floyd jr took out Ortiz like rag doll regardless of the sucker punch the guy couldn't get up means it was a really heavy punch. Cotto was also backing up, I guess Floyd jr gets the hang of his cycling out PEDs while USADA gives him tips. Floyd jr turns into a hulk on fight night no wonder crying out PEDS can avoid suspicions with Mayweather commission it's a win win.

 

Because Ortiz had already taken a lot of big shots. He was on his way out anyway Floyd just helped him out.

 

fight being fixed is a possibility.

 

Did anyone watch the 24/7 for that fight? Mayweather looked kind of small in that scene where he cursed out his pops. By fight night though, he was all diesed up. It's pretty obvious that he's juicng during training camp. The fight was also fixed, it was a sucker punch, and Mayweather loaded his gloves.