Batman With Thor's Hammer VS Teams...
Batman somehow gets Thor's hammer to work for him. He also has a day of prep time. His opponents get none.
Helping Batman is Spiderman (doc ock spidey).
Day One: Iron Man and Hawkeye.
Day Two: Superman and Wonderwoman.
Day Three: Darkseid and Thanos. He doesn't have to defeat these guys, just be able to fight them for 3 minutes and not get killed. Leaving them so embarrassed that they literally retire since they can't kill Batman in 3 minutes between the two of them.
Battle Location: Gotham city.