Lets say he knee cuts towards your left, That means you need to block his knee with your right or under hook the other leg.
I like to use my right arm as a blocker so then i knee him in the ass he has to base on his hands giving him chance of knee slicing, The back step will be there but you will easy deal with that then you learn to do jedi mind trick or just follow him around on a single leg.
I feel the issue comes then you dont track the knee slice leg