For this achievement, you have to defeat Hector Domingo AKA: "Ming", who is number 6 on the Blacklist.
The requirements to face him are:
(7) Race Wins
(4) Milestone Events
His ride is Lamborghini Gallardo and he is a bit harder than other racers to beat, he mainly uses his speed on straights to overtake you, just make sure you match him and you'll beat him easy, handle well on corners thats the key, he ain't very good on corners, except in his speedtrap race, the circuit one should be a breeze, If you get the pink slip for this car this will help MAJORLY, his Lamborghini is an AMAZING car to get, There may be better but it saves a lot of cash and time, Try and get it if possible!