His first defence of his newly won title came as part of Frank Warren's "Magnificent Seven" fight card, which took place on 18 September 2010 at the LG Arena in Birmingham. His opponent for this defence was the undefeated Ukrainian prospect Alexander Frenkel. Despite a tentative opening round Maccarinelli improved and managed to rock his opponent in the fourth round with a right hand. A clash of heads in the sixth led to a cut developing over his right eye, however the fight still appeared to be going Maccarinelli's way until he was knocked down heavily towards the end of round seven by a left hook from Frenkel. Despite managing to rise by the count of nine he was extremely unsteady and appeared to be in no position to defend himself. However the referee allowed the bout to continue, only for it to be stopped a few seconds later when a three punch combination from Frenkel led to a second knockdown. The final blows were struck with such ferocity that Maccarinelli was knocked unconscious and required oxygen and medical attention before being able to leave the ring. At the time of the fight there was heavy criticism from both journalists and fellow boxers at the decision by the referee to allow the fight to continue after the first knockdown, when it was clear that Maccarinelli was in no position to defend himself.