I cannot find the video to accomadate this one.  But when Orcas step into an area they stomp great whites.  They have been known to take advantage of sharks neurosystem and ram them and flip them over (a flipped over shark experiences a paralysis where they don't care,  their fear is gone and pain is nothing while orcas feed on them alive, matter of fact they hate the taste of shark they just want them dead.).  Great Whites in the video im looking for migrate well over 2k miles when they encounter Orca's, and Orcas prefer to feed on Sea lions and other food, so they bully Sharks out of their feeding area.