Undefeated Artur Beterbiev (Russia), 37, defeated Joe Smith Jr. (USA), 32, in their bout in New York.
Beterbiev's WBC and IBF belts and Smith Jr.’s WBO belt were contested in the professional boxing light heavyweight division.
The Russian won by knockout in the second round.
Beterbiev took his 18th victory in as many fights—and all by knockout.
Joe Smith Jr. has a professional record of 28 wins and 4 defeats.