Anyone who has ever boxed knows size difference is one of the biggest factors

Stamina, stamina, stamina... Cardio, cardio cardio!!!!

If you have that all you really have to do is outlast your opponent and let him kick his own ass.

Examples: Ali vs Foreman
Mayweather vs Everyone since 2012
Pacquiao vs Margarito/Cotto/ De La Hoya (Roids or not it was not Manny's power but his constant staying power due to great stamina)
Lara vs Williams
Toney vs Holyfield and Peters( Peters was bigger yet Toney stayed in the booth.)
Jones Jr. vs Ruiz
Haye vs Valuev

 

I almost forgot, you gotta have a chin because you will get hit for the first few rounds with strong shots.
I don't have good stamina so I rely on the first 3 rounds to try and be slow. Boxing is hard work even trying to stay in alright shape. Somebody with great stamina like Garcia V Peterson and I'm outta there.

 

I get it, you love Pacquiao and are still in serious pain about Mayweather beating him.

:hi:

 

yeah, cause Mike Tyson was so much bigger than the majority of his opponents...!!!

 

I guess that's why there are weight divisions then ! lol

 

smh Like you have ever boxed in a ring before.

 

Yup, size does matter. That's why Bob Arum is trying hard to feed Rigo to Lomo.

 

As someone who has boxed in gyms against many shapes and sizes. I would say height tends to be the bigger problem. Bigger tends to be slower. I weigh about 165-175 and have fought guys in their 200's, that were no slouches. Taller guys that had a weight advantage were trouble. I'm about 6'1.5 btw

 

Yes, it's also amazing how Floyd has been successful fighting guys who rehydrate to over 160 pounds just like Manny has, they are both average sized welterweights at best.

 

Size is hugely important, but so are a number of factors. Like the expression goes, a good big one beats a good little one. But there are examples of smaller beating bigger, Jones v Ruiz comes to mind (although there was only about 2 inches and 25 pounds difference at the time). There's no question, though, there's a reason superheavies keep getting taller and bigger; it helps!

Personally, I never fought amateur or pro, but sparred some in boxing gyms. I'm 6'3, 220 when younger, 260 now, usually had to spar with much smaller guys, usually more than held my own even though they went full force on me and I had to hold back. But one guy when I was 260 was about 5'11 or 6'0, 160 and super fast. He couldn't hurt me, but I couldn't touch him. If it was a bout I would have been embarrassingly shut out. If I landed, it might have been over, but I kind of doubt I ever would have landed. Along the same lines I'm sure there are low level pro superhw's who would lose to top contender welterweights.