ジュニオール・ドス・サントス
Velasquez was expected to make his first title defense against Junior dos Santos, with a target date of November 19, 2011, at UFC 139, but the fight was later moved to November 12, 2011, to headline the first UFC on Fox 1 event. Velasquez suffered his first loss, via KO (punches), at 1 minute and 4 seconds of the first round. While not public information at the time, it was later revealed that Dos Santos already had a minor knee injury (a torn meniscus), and took an injection of cortisone into the knee before the fight, followed by information revealing that Velasquez had re-injured his rotator cuff approximately a week before the fight. Junior dos Santos would undergo knee surgery following the fight.