Erislandy Lara
Jack's next fight was due to take place on 12 December 2014 against Mexican boxer Francisco Sierra at the Alamodome in San Antonio, Texas on the undercard of Erislandy Lara vs. Ishe Smith. Sierra gained 20 pounds between the weigh in and the opening bell, coming into the ring at 192 pounds. Jack dominated the fight from the start. The end came in round 6. Jack landed some combinations, which went unanswered by Sierra. The referee stopped the fight at 1:58 giving Jack the TKO win.