Yeah the part where you do the major damage is during the tornado/spinning thing. All you have to do is dodge 5 of his attacks where he sticks his claw out and he spins out leaving him open for attack, it's not that hard, you either have to duck or press up, and you even get a warning. If you still can't dodge them, then try using slow until you see where he's going to hit you, then let go of slow and quickly press either up or down depending on where he's attacking. You can't dodge his attacks while using slow, although it's easier, it doesn't count as a dodge and he won't spin out and you won't be able to attack him.
Once you have dodged five attacks, just pound him with Slow/zoomed punches, or that boomerang technique that Vlad suggested. You'll get there eventually, just practice!