ERFURT, Germany -- Alexander Povetkin of Russia defeated Ruslan Chagaev by unanimous decision Saturday to claim the vacant WBA heavyweight title.The title was Wladimir Klitschko's following the Ukrainian's victory over David Haye by unanimous decision in Hamburg last month, but was declared vacant when the WBA elevated Klitschko to "super champion" status.Povetkin, the 2004 Olympic heavyweight champion, remains undefeated after 22 fights (15 KOs), and becomes the mandatory challenger for Klitschko.Read More... More on Combat Sports