I did this on the first boss challenge in Adventure Mode which is against Ripper Roo. To unlock this boss challenge you must place first in the beginning 4 races available in Adventure Mode.
My piece of advice is get in front of the boss as soon as possible and evade the boss' power-ups. Ripper Roo specialises in TNT so do not stay directly behind Ripper Roo and soon as you are in front, drift boost and keep the lead as you cannot be hit by the boss' power-ups if you are in front of the boss!
I made this video to help:
Hope this helps.