2013 Event American boxer Floyd Mayweather defeats Robert Guerrero and retains his WBC Welterweight title in a unanimous decision 1983 Event Harm Wiersma retains checkers world championship 1983 Event Rudi Koopmans retains European middleweight title 1982 Event Ingrid Berghmans (Netherlands) retains judo's world championship 1981 Event Anatoly Karpov, U.S.S.R. retains world chess championship 1955 Event Pancho Gonzales retains tennis title by winning a tournament playing under table tennis rules 1949 Event Richard Button retains world figure skating championship in Paris
