Carl Lewis did not successfully defend his title, he was defeated by Ben Johnson. If Lewis' drug use is dismissed, Johson's must be as well, meaning that Lewis was defeated in 1988. Alternately, both Lewis and Johnson must be disqualified, meaning that Lewis did not win in 1988. Lewis did not defend his title.

Congratulations Mr. Bolt. You are the first man to defend the title.

(Unless of course you are doping too)