Artur Beterbiev (14-0) strengthened his status as one of the world's top light heavyweights and a worthy foe for Sergey Kovalev with a fifth-round stoppage of Radivoje Kalajdzic (24-2) in the main event of the Top Rank card in Stockton, California, which aired on ESPN on Saturday night. It was Beterbiev's 14th stoppage victory in 14 fights. Read more http://www.espn.com/boxing/story/_/id/26673505/beterbiev-beats-kalajdzic-remains-undefeated