Watch from the guard for your opponent to raise a leg in order to gain leverage and space to better strike.

Hook under his knee as you spin towards his leg(and thereby moving out of his best striking position) while you grab and pull down & in on his opposite tricep. This will unbalance him and force his weight to your (L) upper corner.

Pull down on his arm and let his shifting weight pull you up with him as you roll together. (keep tight against him!)

Finish the roll and you end up in the mount!