Glaube Feitosa
Due to his standing as one of the world's best heavyweights, he was invited to the 2009 K-1 World Grand Prix. At the "K-1 World Grand Prix 2009 Final 16" in Seoul, South Korea on September 26, he rematched Glaube Feitosa. After three rounds of fighting, Zimmerman was named the winner via majority decision (29–28, 29–28, and 30–30) and qualified for the final eight.