The main event was a rematch between UFC Heavyweight Champion Brock Lesnar and Interim UFC Heavyweight Champion Frank Mir. This championship unification bout occurred as a result of former UFC Heavyweight Champion Randy Couture's year-long resignation from the promotion. During his absence, the UFC created an Interim championship, which Antônio Rodrigo Nogueira won by defeating Tim Sylvia. Nogueira and Mir were opposing coaches on The Ultimate Fighter: Team Nogueira vs Team Mir, and fought for the interim championship at UFC 92. The co-main event featured Georges St-Pierre, defending the Welterweight Championship against Thiago Alves. Alves entered the fight after consecutive victories over three top UFC welterweights: Josh Koscheck, Matt Hughes and Karo Parisyan.