A rugby fan needed emergency surgery after he was attacked in a car park outside Halliwell Jones Stadium in Warrington.
The 32-year-old had been at the Championship Grand Final between Halifax and Featherstone on Sunday.
He was returning to where his coach was parked in Dallam Lane when he was assaulted.
Cheshire Police said the Halifax supporter suffered serious head injuries and had to undergo surgery.
Detectives said the coach park was busy when the attack happened at about 2015 BST, with many fans returning to their coaches.
They urged anyone who witnessed the incident to contact them.