Twelve years after competing in her first Games, Dezillie qualified for her third Belgian team, as a 31-year-old, in the Europe class at the 2004 Summer Olympics in Athens, by placing among the top 40 and receiving a berth from the 2003 ISAF World Championships in Cadiz, Spain. Dezillie got off to a fantastic start of the series with a substantial lead over the rest of the fleet, but a yachting malfunction in the midway and a disastrous feat on the last few races slipped her out of medal contention to fifteenth overall with a net grade of 133.