Warner qualificated for the 1992 Olympics in Barcelona, Spain. At the games, he won gold. This was the best year in his Table tennis career. He was the third man to win the Grand Slam. To win the Grand Slam, a person has to be the winner of the World Cup, Olympic gold medal and World Championship, all at the same time. He won the World Cup (1990), the Olympic Games (1992) and the World Championships (1987, 1989). He did not win the European Championships that year. He lost in the singles against Jörgen Persson. That year he was number one in the world rankings. From 1993 t0 1996, he had many problems with his body. 