Beat him up standing up.
It is in the mind certain martial artists walk certain paths you supposed to know where to walk and when to walk unless you are looking to initiate the fight unless you walk the right path you won't deal with nusaince of the mind of other imbiates.
attack the knee with kicks, look out for his kicks,try to grab his leg, keep moving
Dont
use your speed & size dont matter.
IF you have a hard time bringing him to the ground. Lets say hes 4-8 inches taller than you