Experts' picks: Saturday's fights

Two of boxing's brightest young stars will headline separate cards in the same city Saturday in Las Vegas. Mexican stars Julio Cesar Chavez Jr. and Saul "Canelo" Alvarez enter different tests under entirely different circumstances. Chavez (46-0-1, 32 KOs) brings his middleweight title and unbeaten record into a showdown against lineal champion Sergio Martinez (49-2-2, 28 KOs) at Thomas & Mack Center. Meanwhile, just two miles away at the MGM Grand, Alvarez (40-0-1, 29 KOs) defends his junior middleweight title against upset-minded Josesito Lopez (30-4, 18 KOs), fresh off a shocking June victory over Victor Ortiz.

Below, our ESPN.com boxing experts pick the winners of the main events, along with the undercard fighter most likely to steal the show Saturday.