Castellanos of Celaya, México, was the aggressor for the majority of the fight, stalking Miami’s Gamboa by way of Guantanamo, Cuba, and scoring a hard right hand from different angles almost at will. A straight right in the 3rd sent Gamboa down for the first time in the bout. Despite with a little over of the round left, Gamboa was able to survive the round but early in the fourth Castellanos scored another a right, an overhand one, to drop Gamboa again.
Gamboa seemed to get his footing and boxed well for the next couple of rounds but Castellanos kept coming forward and pressuring the Cuban. After a busy finish in the seventh where Castellanos scored a hard body shots to the body, Gamboa decided to not come out for the 8th giving Castellanos the TKO victory.
The bout marked the second fight for Gamboa under the Golden Boy Promotions banner.