The event was held over a 10km run, 40km bike, 5km run course, from the Mosgiel Motorcycle Club.
Creasy (31), a sports physiologist with Triathlon New Zealand, was quickly into his work, taking a 48sec lead into the cycle stage.
But a strong challenge from Chris Keogh quickly removed this advantage and Creasy had to work hard to stay in touch with the lead.
Keogh continued to apply pressure throughout the cycle stage, stretching a 10sec lead at the halfway stage out to a 25sec advantage for the 5km run to the finish.
But by midway through the run home, Creasy had turned the tables on Keogh and gradually extended his lead, crossing the finish 57sec clear of Keogh in 1hr 56min 58sec and just 9sec adrift of Jason Palmer's course record. Third was basketball convert Mitch McRae in 2hr 5min 34sec.
Victory caps off a successful 12 months for Creasy, in which he won the half ironman in Ashburton last November and collected age-group titles in the world triathlon long-distance championships in July, age group titles in both standard and sprint distance triathlon and an age-group title at the national half iron man championship.
"That was a great hit-out," Creasy said of his victory yesterday.
He will contest the national duathlon championships in Taupo in two weeks, followed three weeks later by the world triathlon championships in Auckland.
In the women's event, Katie Menzies (25), a community and schools adviser with Sport Otago, showed the benefits of racing professionally in the United States for the past three months.
Although returning to Dunedin cash poor, she is much richer for the experience, as evidenced by the dominant manner of her victory in the open women's section yesterday.
Menzies impressed at the top end of the field throughout to cross the finish in an impressive 2hr 8min 25sec. Second was Megan Balchin in 2hr 29min 12sec, and Olivia Moon was third in 2hr 32min 28sec.
