To do this achievement you need one friend to help you as you need to play online to get it. And the achievement seems to be a bit glitchy, and only pops when your not the host. So your friend need to start a private match, then set it to Race and map to White faction base. So when your friend is on the last lap kill him 3 times.
YA BILLY commented and said that you can do this local with a extra controler.