You can also be out of range, dash into the thrust and still get the Miriki Counter off. You will want to punish this attack as much as possible as it is easy to Miriki Counter. If he does a second large sweep and a number of other attacks, he will follow this up with a Perilous thrust attack. This will do a lot of posture damage though. If you do not feel confident doing this, you can deflect it however, he will follow up with a second attack that is the exact same. If he lifts his blade with both hands above his head, you want to dodge just at the last second, before he attacks.
Get as far from him as you can, as he is about to perform a spinning attack that has a lot of range. If he dashes towards you at an angle and you see a wind effect gathering in his sword, you want to run away. You can get him to repeat this attack fairly often by clashing blades with him after he attacks you. This is another attack we want him to do a lot. When he does this, and any time he kicks you, he will immediately follow up with a Perilous thrust attack which you want to punish with the Miriki Counter. If you are attacking him, and he is deflecting he will follow up by kicking you. You can always dodge this by running left.
At any point, he can also do a very quick Perilous slicing attack.