It depends more on your fighting skills than on whether or not you are in "top physical shape". You can be in great shape but if you don't know how to punch or block or dodge a punch, you are in trouble. Also, who can hit the hardest? Connecting with the first punch and that punch being hard enough to put the other guy down is a major advantage.
I've seen smaller guys (and gals) win against bigger gys (or gals) because they have better skills. I'm pretty skinny and not all that strong, but if I get in a fight with a bigger and stronger girl (or guy) who has no fighting skills, I've got a good chance of winning, because I know what I'm doing.
Also, somebody who has no fighting skills in real life is going to be shocked as hell when the other guy connects to their face the first time and IT REALLY HURTS! That will make you freeze up, especially if it knocks you back. You won't know how to recover, you won't be expecting it, and in those few seconds it takes to regain your balance and thoughts, the other guy will have you on the ground.
So, I'd pretty much bet against the guy with no real life experience, no matter what kind of shape he's in. Riding a bike doesn't really do much to get you ready to fight somebody, except to build stamina.
_________________
I'm giving it another shot. We will see.
My forum is still there and everyone is welcome to come join as well. There is a private women only subforum there if anyone is interested. Also, there is no CAPTCHA.

The link to the forum is
http://www.rightplanet.proboards.com