i did alot of thai boxing.
id spar him, just for the fun of it, but hear this.

box him.
if you try and get in close and slug it out youll be smashed with bare bone (ala eblows and knees).
look on the internet for a way of stopping low roundhouses... you have to raise your shin into the kick to stop it smakcking your thighs.
make sure you keep your eyes on his face, and dont watch his feet, youll probabely end up being dropped by hands.

use straight punches and speed