The 28-year-old Olympic medallist faced a field of teenagers, and her experience proved superior.
After a clean turn at the halfway point, Haughey steadily stretched her lead to more than a full body length before touching home comfortably in 52.88 seconds.
Fellow SAR swimmers Li Sum-yiu and Gilaine Ma completed the podium in second and third respectively.
The victory capped a stellar weekend for Haughey, who also clinched gold in the 50 metres and 200 metres freestyle on Saturday.













