Malc wants you to prove you've got balls and take part in a race with him.
Get a bike and head to the start point. After that it's just a regular street race where you can whack people off with the bat.
I ended up coming 3rd because I got hit down an alleyway at the start and couldn't get turned around, so I don't know the reward for winning. You can only do the mission once, so maybe make a save game before it if you want to guarantee a victory. Whether you win or lose, this mission is complete.