Ukraine's Oleksandr Usyk extended his undefeated record with a unanimous points win over Dereck Chisora on Saturday, ending the British fighter's possible last shot at a world heavyweight title bout. Eight years after losing to Vitali Klitschko in his only attempt to become heavyweight champion, Chisora struggled against 2012 Olympic gold medallist Usyk. The Ukrainian, a former undisputed cruiserweight champion, has won all 18 of his professional fights. He now becomes the mandatory challenger for one of Anthony Joshua's belts after his 117-112, 115-113 and 115-113 win. dj/jc