Dirrell and his younger brother Anthony began boxing while still in elementary school in their hometown of Flint, Michigan.
A southpaw possessing exceptional athleticism and the ability to switch-hit, he was considered among boxing's top young prospects following an extensive amateur career.
Dirrell defeated future world title challenger Curtis Stevens on HBO's Boxing After Dark in June 2007.
[11] Thirteen months after that, Dirrell made a return to the ring with a unanimous decision win against Michael Gbenga after knocking him down in round 9.
Eighteen months after the Gbenga fight, Dirrell returned to score a fifth-round KO against Vladine Biosse.
DeGale gained two knockdowns in the second round, which proved to be the difference as he won a unanimous decision over Dirrell to win a 168-pound world title.
After the fight was stopped, Dirrell's trainer and uncle Leon Lawson approached Uzcategui and sucker-punched him before fleeing the scene.
Dirrell finished his opponent early, by dropping him three times in the third round, forcing the referee to stop the fight.