His first professional match as a snooker referee was in 1993 (between Tony Drago and Steve Davis). In 2003 he became the first man from outside the United Kingdom to referee the final of the World Snooker Championship, and he refereed the 2006 World Final between Peter Ebdon and Graeme Dott. Verhaas was in control of all three Masters finals which the late Paul Hunter won, and he describes them as his most memorable matches.