This is unlocked on level 3 of the championship
You need to go backwards from the start and go thru the hidden exit
Championship gameplay options:
ResistancePlayer: x10
Rivals: x1
Rules# of rivals: 1 or 2 (two will make it easier to score 2K)
Event duration: 3m
Idle disqualify: 3m
No hit disqualify: 3m
In video at 4:10
Achievement Walkthrough: