In 1987 he competed in the inaugural World Touring Car Championship for the Eggenberger Motorsport works Ford team driving the RS Cosworth and RS500 versions of the Ford Sierra. His teammates for the championship were West German pair Klaus Ludwig and Klaus Niedzwiedz and Englishman Steve Soper, who was his regular co-driver. He won Round 8 of the championship, the Bob Jane T-Marts 500 at the Calder Park Raceway in Australia, which was run on a combined road course and the NASCAR-style "Thunderdome" high-banked oval, driving with Soper, and finished fifth in the championship (Dieudonné and Soper had won the Bathurst 1000 in Australia the week before the Calder race, but were disqualified for illegal wheel arch modifications). He finished third in the ETCC in the 1988 season, again for Eggenberger. Dieudonné competed in one round of the 1989 British Touring Car Championship for JQF Engineering with Chris Hodgetts in a Ford Sierra RS500. That same year he was a 1989 24 Hours of Le Mans GTP Class winner with Hodgetts and David Kennedy for Mazdaspeed. The 1991 24 Hours of Le Mans saw him finish eighth for Mazdaspeed in a Mazda 787 in the C2 Class.