Jason Bourne vs Batman
Shortly after the events of The Bourne Identity, Jason Bourne's partner, Marie, has been kidnapped by his former CIA employers, who have threatened to kill her if he does not do as they demand. And what they demand is that Bourne go to Gotham City and kill Batman.
The CIA will give Bourne any weapons, equipment and information he needs in order to complete his mission, but he will receive no help from any other agents, or any extremely powerful explosives. It must be a stealthy kill, and be as unnoticeable as possible. The only information they have on Batman is what certain criminals and members of the press they interviewed have said about him.
So, to summarize:
Jason Bourne, armed and informed by the CIA, from just after The Bourne Identity
VS
Batman, unaware of Bourne's existence, let alone his intention, from just after Batman Begins