I struggled to hit every overhead punch because he opens his mouth before the window to hit his mouth so even when I hit him mouth he would block but is not that bad really.
I block a closed mouth punch then get a star. Then counter an open mouth very early to get 8 counter punches. After that he does 2 more closed mouth punches, block the first 1st one to get a star then cancel the 2nd. Then counter another open mouth for 8 counters again but 2 star punch for the last stun hit. Then cancel 1 last closed mouth punch, after he does his hippo hug and counter with a gut punch for an iko. 3 frame perfect inputs, that's not to bad.