Darkseid & Batman vs. Thanos & Adam Warlock
Okay, here's the unlikely senario:
'Seid and Batman are sent to the 616 Marvel Universe while Thanos and Warlock are sent to the DC Earth-1 Universe. The goal of each duo is to destroy the universe that they are each currently in, so that they may return home. The first to complete their mission wins. If neither team is able to complete the challenge, the team who deals out the most damage/death/havoc wins. There is no time limit. They also have no knowledge of various artifacts of power initially. Winning through strategy, manipulation, or brute force, doesn't matter how each team wins, so long as they do.
How's this go?