Upcoming fight help please?

Ok, i'm an armature mma fighter with record of 6-4-1 I use Brazilian Jiu-Jitsu and kickboxing I need my record to go up and I really can't use any leg locks because of the strain on my right arm and i have and upcoming fight against a Karate black belt who's record is 9-2-0 so I need a technique for submitting a fighter without using my arms please, please help me...