Semmy Schilt
On April 3, Zimmerman faced Golden Glory teammate Semmy Schilt for the K-1 Super Heavyweight Championship at the "K-1 World Grand Prix 2010 in Yokohama". Although Zimmerman was able to find Schilt's chin on a few occasions, Schilt dominated the match and took a unanimous decision (30–27, 30–27, and 30–28) win to retain the title.