Before the fight, Superman has to run out on an Emergency, and contacts Batman to tell Thor he's throwing the fight. Bats is busy, and sends Cassandra Cain Batgirl to deliver the news..
Cass finds Thor at the Fantastic Four towers. As luck would have it, he had some of Sue Richards cooking, and became deathly ill, and was about the contact Supes to throw the fight himself.
Cass, instead of delivering the message, gets the itch to fight herself, and suggests they should get champions to stand in for them, with Cass acting as Supermans representative. So Thor thinks about it, and ends up calling Electra.
The fight takes place in an adamantium cage. Electra represents Thor, Cass represents Superman.
Asgardians spend a lot of time at feasts so yes they do eat, drink, get drunk and do "other things" as John Carpenter's Star Man once politely described.