Question: Vitali Boot is a German amateur boxer best known to win the bronze medal at super heavyweight at the 2001 World Amateur Boxing Championships, there he beat Poland's Grzegorz Kielsa (20:14), but lost to which eventual winner, an Uzbek former professional boxer who competed from 1997 to 2016?
Sentence (from "Ruslan Chagaev"): He is a two-time WBA heavyweight champion, having held the full world title from 2007 to 2009, and the Regular title from 2014 to 2016.
Relevant evidence: No