On Saturday night, in front of 15,000 people at the Thomas and Mack Centre on the outskirts of Las Vegas, Castillo gained revenge for his loss in May when he knocked out Corrales with a single left hook in round four.
There were no titles at stake, because Castillo had weighed three and a half pounds over the stipulated limit and had opted to forfeit $120,000 (£68,000) rather than lose the extra poundage. However, the Mexican had a private wager with Gary Shaw, who promotes Corrales, that he would win by knockout.
The May fight was sickeningly hard. Saturday's contest followed a similar pattern but Corrales often looked vulnerable. Castillo waited patiently and connected cleanly when the moment came.
"I made a stupid mistake and he caught me with a great shot,'' said Corrales.
It is understood that there is a return clause in their contract, but it remains to be seen at what weight their third fight will take place. It is obvious that neither of them can make the 135lb lightweight championship weight limit.
Nevada boxing officials make fighters in championship contests weigh in hours before the first bell and on Saturday Corrales was 149lb and Castillo 147.Reuse content