Sprawl and more sprawl, after that, try to break some finger I think (remember that, we do not have rules or judges). They have the same skill that we to protect to complex parts like arms and legs.. Respect to the blows, i believe that the UFC already demonstrated that they are not so efficient with them.
I think that our greater weapon is to always attack his attack (irimi) leaving its trajectory of entrance, always.
PD: And now, to sweeten the situation, How to neutralize to a Aikidoka?