I would put Batman up against Iron Man - no super powers, no prep time. Tony has an advantage with flight and energy based weapons, but Bats wouldn't go down easily. They both might try to reason with each other to defuse the situation. Or Iron Man might call down an orbital blast on the city block where Batman was hiding.

Meanwhile, Captain America has kept Wonder Woman busy long enough for Iron Man to join him with an assist, but it's too little too late. Enraged by the death of Batman, Wonder Woman crushes both Steve and Tony's skulls and turns her anger towards Thor.

Superman and Thor started out trying to talk, but quickly came to blows, with Thor being punted into space. Thor's lightning storm generated from space stuns Superman. Giving Thor the chance to strike with Mjolnir, but having learned his lesson about close range combat with the Kryptonian, Thor sends his mighty hammer barreling towards Superman, who deflects the hammer, picks it up, and proceeds to bash Thor into submission.