original question: Which tournament champions were ever defeated by [Xavier Malisse]?
answer: stan wawrinka, roger federer
answer type: Tennis Tournament Champion.
auxiliary information: Xavier Malisse is a retired Belgian tennis player. Born in the north-western Flemish city of Kortrijk and nicknamed X-Man, he is only one of two players from Belgium to have been ranked in the top 20 of the ATP tour, with a career-high singles ranking of World No. 19.
What are the name of the tournament champions that were ever defeated by [Xavier Malisse]?