Don Myrah wins the men's XC World's at Mammoth for Ritchey in 1989. I think he also took the CX title that year ... he tore up the CX circuit and still does!
Myrah actually signs for Yeti and Campagnolo for the 1990 season, but Yeti won't make a bike to his specs so he backs out and signs with Fat Chance. The change came late so Myrah rode the first race or two on a blue Ritchey in Fat Chance livery. I think he won the opening round on it: