[EliteNinja]

Best thing to do is bail in that situation.
You're alone. He may have backup on top of having a knife.
You have no buddies to back you up.

First thing you learn in ninja school is that an unarmed expert at martial arts is still at a 2-to-1 disadvantage to a random dude with a knife.

But if you're trapped, go for the ol' broken beer bottle trick. Or do a flying roundhouse kick to his head.