Wow! I think its just physics, he's bigger and stronger and he definitely knows what he's doing. But i'm sure you can kick the ass of a regular guy, like me. Please don't do it :)
But it's just practice. You'll get a lot better, maybe next time you'll take that guy.
Thanks! Yes, it is all about practicing, trying new things, failing, then trying again... small adjustments sometimes can make a big difference :-).