Yanagisawa will now be using all of his moves against you. One of his favorites in his counter, which will have him toss you to the other side of the screen. His moves can all remove large chunks from the stun gauge, so be careful if you get hit by any of them.
There are two good ways to defeat him. First, keep using the smash and rend move, if you do this a short distance away from him he will usually get hit by it. This will also get him stunned after he's hit by three or so of these moves. The other way is to keep using crouching strong kicks, as he's not too good at defending himself from these. It he does block it, wait as he'll usually counter with his own sweep. Once you've blocked that, try sweeping him back and repeat until he's down.
What happens next depends on who won this fight: