For this achievement, you have to defeat Jade Barrett AKA: "Jewels", who is number 8 on the Blacklist.
The requirements to face her are:
(5) Race Wins
(4) Milestone Events
(1,180,000) Bounty
Races:
Sprint Race
Drag Race
Her ride is Ford Mustang GT and she is an easy racer to beat, she mainly uses speed on straights to overtake you in her sprint race, just make sure you match her and you'll beat her easy, handle well on corners thats the key, she ain't very good on corners, except in her sprint race, the drag race one should be easy if you know when to shift, make sure its a PERFECT shift.