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?
Context: Brent "Koko" Kosolofski ( (1964--) 22 1964 (age (2017)-(1964)-((11)<(08)or(11)==(08)and(30)<(22)) ) ) is a Canadian amateur light heavyweight and professional light heavy/cruiser/heavyweight boxer of the 1980s and '90s who as an amateur represented Canada at light heavyweight in the 1986 World Amateur Boxing Championships in Reno, Nevada, United States, losing to John Beckles of England, represented Canada and won the bronze medal at light heavyweight in the Boxing at the 1986 Commonwealth Games, in Edinburgh, Scotland, losing to eventual gold medal winner James Moran of England, and represented Canada at light heavyweight in the Boxing at the 1988 Summer Olympics in Seoul, South Korea, losing to Andrea Magi of Italy, and as a professional won the Commonwealth light heavyweight title, his professional fighting weight varied from 173 lb , i.e. light heavyweight to 199 lb , i.e. heavyweight. Alexander Povernov (born 17 February 1978) is a German amateur boxer best known to win Bronze at the 2005 World Amateur Boxing Championships at Heavyweights with 201 lb/91 kg limit. Constantin Titoiu is a retired amateur boxer from Romania.  At the 1982 World Amateur Boxing Championships he won the bronze medal in the flyweight division (– 51 kg).  In the semifinals he was beaten by eventual silver medalist Michael Collins of the United States.  He also received a bronze medal in the 1983 European Amateur Boxing Championships. Li Yang () is a Chinese amateur boxer best known for winning a bronze medal at featherweight at the 2007 World Amateur Boxing Championships in Chicago. Kurban Günebakan (born September 13, 1978 in Kars), nicknamed "Kaplan" (English: Tiger ), is a Turkish amateur boxer best known to win the bronze medal in the super heavyweight division at the 2006 European Amateur Boxing Championships held in Plovdiv, Bulgaria.  He competes for Bursa Emniyet, the sports club of the Police Department in Bursa. Markus Beyer (born 28 April 1971) is a German former professional boxer who won the WBC super middleweight title.  As an amateur he represented Germany at the 1992 and 1996 Olympics in the light middleweight division.  He also won a bronze medal at the 1995 World Amateur Boxing Championships and silver at the 1996 European Amateur Boxing Championships. Ruslan Shamilevich Chagaev (Tatar: Руслан Шамил улы Чагаев , "Ruslan Şamil ulı Çağayev"; Uzbek: "Ruslan Shamil'evich Chagaev" ; Russian: Руслан Шамилович Чагаев ); born 19 October 1978) is an Uzbek former professional boxer who competed from 1997 to 2016.  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.  To date, Chagaev remains the only Asian boxer in the history of the sport to hold a heavyweight world title by any of the four major sanctioning bodies. The AIBA World Boxing Championships and the AIBA Women's World Boxing Championships are biennial amateur boxing competitions organised by the International Boxing Association (AIBA), which is the sport governing body.  Alongside the Olympic boxing programme, it is the highest level of competition for the sport.  The championships was first held in 1974 Havana, Cuba as a men's only event and the first women's championships was held over 25 years later in 2001.  Formerly known as the World Amateur Boxing Championships and the Women's World Amateur Boxing Championships, the men's and women's competitions are held separately and since 2006 the biennial championships have been held in alternating years. William "Billy" 'The Kid' Irwin ( (1968--) 20 1968 (age (2017)-(1968)-((11)<(05)or(11)==(05)and(29)<(20)) ) ) born Niagara Falls, Ontario, is a retired Canadian amateur lightweight and professional light/light welter/welterweight boxer of the 1990s and 2000s who as an amateur won a bronze medal in the Boxing at the 1991 Pan American Games in Havana, Cuba, losing to eventual silver medal winner Patrice Brooks of the United States, represented Canada at the 1991 World Amateur Boxing Championships in Sydney, Australia losing to Julien Lorcy of France, and represented Canada at the 1992 Summer Olympics in Barcelona, Spain, he was stopped in the second round of the lightweight division (– 60 kg) by Ronald Chavez of the Philippines, and as a professional won the Canadian Professional Boxing Council (CPBC) lightweight title, Canada lightweight title, International Boxing Organization (IBO) lightweight title, World Boxing Council (WBC) Continental Americas lightweight title, and Commonwealth lightweight title, and was a challenger for the International Boxing Federation (IBF) lightweight title against Paul Spadafora, and World Boxing Association (WBA) World lightweight title against Juan Díaz, his professional fighting weight varied from 133+1/2 lb , i.e. lightweight to 142 lb , i.e. welterweight.  He retired from boxing after losing to Juan Diaz in 2005, his second unsuccessful world title challenge.  His final record was 42(30)–6–0. 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 eventual winner Ruslan Chagaev.
Answer: Ruslan Chagaev