Klitschko defeated WBO Heavyweight Champion Sultan Ibragimov at Madison Square Garden in New York City on 23 February 2008 to unify the IBF, IBO and WBO Heavyweight titles. The Klitschko-Ibragimov fight was the first heavyweight unification since Holyfield-Lewis in 1999. The unification clash with Ibragimov proved to be a huge disappointment for fans. Klitschko was very dominant from the first bell. He backed Ibragimov into a corner and proceeded to push down Ibragimov's glove with his left hand so he could not throw a punch. Though Klitschko won every single round, the crowd in New York City began booing after the second round. The boos and jeers increased as the fight progressed in the same fashion. Ibragimov's corner was almost silent from the sixth round onwards, unable to give their man any meaningful advice. Klitschko did not fight again in the United States until 2015 where he defeated Bryant Jennings .