The answer is the French Open. Edberg reached the final twice, in 1989 and 1990, but lost both times to Ivan Lendl and Andrés Gómez respectively. He won the Australian Open in 1985 and 1987, Wimbledon in 1988 and the US Open in 1991 and 1992
Serving Up Success: Unraveling the Legacy of Stefan Edberg