Fonte
FIFA.COM
"With respect to the history of the FIFA Club World Cup and intercontinental club competitions in years gone by, such as the Copa Rio in the 1950s, the FIFA Executive Committee endorsed the view that the first edition of this competition was held in 2000 in Brazil where Corinthians became the very first FIFA club world champions. Other tournaments are not considered official FIFA events. "
http://www.fifa.com/aboutfifa/federation/releases/newsid=660747.html