Mares was scheduled to face IBF Champion and No. 3 ranked Joseph Agbeko in the final round of the tournament on April 23, 2011. However, Agbeko pulled out of the fight just days prior citing an injury. The match was rescheduled for August 13, 2011. Mares fought Agbeko on August 13 on Showtime and won the title and the tournament by majority decision. However, the match was not without controversy, as Mares delivered numerous low blows during the match, with referee Russell Mora not penalizing him with point deductions for any of the blows throughout the match. The most infamous of these blows came during the 11th round of the fight, in which a low blow from Mares landed on Agbeko's cup, causing Agbeko to drop. While the low blow was clearly visible to everyone, referee Mora ruled it as a knockdown.