On the January 2007 FIDE rating list , Korchnoi was ranked number 85 in the world at age 75 , by far the oldest player ever to be ranked in the FIDE top 100 . On the January 2007 FIDE rating list Korchnoi was ranked number 85 in the world at age 75 , by far the oldest player ever to be ranked in the FIDE top 100 .