Felix Sturm
Castillejo, then hit Sturm (27–2, 11 knockouts) with three uppercuts before the referee called the fight, making Castillejo, 38 at the time of his upset victory, the oldest man to win a recognized version on the World Middleweight Championship. He lost his title in his first defence against Argentine Mariano Natalio Carrera via a disputed 11th-round TKO. Later on, Carrera tested positive for Clenbuterol and was suspended for 6 months by the WBA, thus Castillejo regained his title on 23 February. . He lost the title 28 April 2007 in a rematch against Felix Sturm.