Walt can't fight period. That comment stated he would BEAT Jesse's ass and I don't buy that at all. Cancer or no cancer, every time Walt has been in a one on one altercation he taken the L decisively too. He was only able to kill that one dealer in that basement because dude was tied up already.That makes no sense, You think Gus or Mike handle problems with their fist only? Uncle Jack and his crew tool up at every chance they get, The stakes are way too high to be fighting hand to hand, and yes Jesse wins only because Walt had chemo and is almost double his age.
Walt strengths has always his brains and his evil ruthlessness. Him getting physical has always been an automatic L unless he has a weapon and even then he needs to sneak up on the person like he did with Mike to guarantee success.