The second-placed horse Humidor who put in a very brave effort is part-owned by former All Black Mark Carter, and his brother Mark and sister Rachel.
Winx latest win sees her become just the second horse to win three successive Cox Plates, a feat previously achieved by the legendary Kingston Town.
The 32,000 fans trackside cheered on the star filly, many of whom were holding up 'Go Winx' signs printed up by race organisers for the day.
Winx is trained by Kiwi, Chris Waller, who was in tears after the race as he paid tribute.
In the lead-up to today's race Waller told Racing.com that Winx was a "heavenly gift".
"She's in fantastic form," he said.
"You don't have to make her run faster. You don't worry about the weather because it makes no difference to her. You don't worry about barrier draws or rivals, unless the next champion is coming through and that doesn't seem to be the case. But you just want it over with."