 Chagaev slowly but steadily climbed up the heavyweight ranks, first avenging the no-contest with a brutal second-round knockout of Calloway.In 2006 he beat undefeated Ukrainian prospect Vladimir Virchis in a close and intense punchfest, and slowly took apart prominent British boxer Michael Sprott.On 18 November 2006, he fought the former WBA champion John Ruiz, and prevailed in a close contest.