THE question is almost impossible to answer: why is Winx so good?
Sydney's super mare makes her return to the racetrack at Royal Randwick on Saturday and, barring unforeseen circumstances, she will record her 18th win in succession in the Group 2 $250,000 Bob Ingham Warwick Stakes (1400m).
Price assessors rate Winx virtually unbeatable as the mare was rated $1.07 on TAB Fixed Odds on Friday.
Winx hasn't been beaten for more than two years and, after this weekend, she could even be rated the best galloper in the world if US champ Arrogate has his colours lowered again at Del Mar in California on Sunday morning.
But even Winx's trainer, Chris Waller, conceded it was very difficult trying to pinpoint one particular reason why the mighty mare was so superior to her opposition.
Waller and jockey Hugh Bowman marvel at Winx's outstanding athleticism and race sense, which complements her competitive nature. But the trainer's theory is more simplistic.
"Winx's determination is something very special," Waller said. "We have seen it throughout her race career. It doesn't matter if the tracks are wet or very firm, she might strike trouble in running, but she will pick herself up and still come away to win. She just doesn't win, either, she wins with something to spare as well.
"It is her determination that sticks out to me - she hates losing."
Winx is a stronger, more muscular mare this time in work but at about 16.1 hands and 530kg, she's certainly not the biggest horse in training.
A recent university study identified Winx's stride and, to be more precise, the frequency of her stride as a clue to her extraordinary ability. Winx's stride length was measured at about 6.8m, which is longer than the average.
But it is the frequency of her stride that is remarkable.
The mighty mare takes about 170 strides per minute - compared to an average racehorse's 140 per minute - which underlines her ability to sustain top speed for longer than her rivals.
It was found Winx has the rare, stamina-sapping ability to quicken and maintain her acceleration to the end of a race, while her rivals are tiring, shortening stride and decreasing speed under pressure. Waller has such faith in Winx's ability, he doesn't feel the need to burden race jockey Bowman with riding tactics.
"We don't over-analyse things with her," Waller said. "We have so much confidence in Hugh Bowman. He is such a great rider and handles these situations so well. The more you complicate these things, the harder it becomes.
"Winx is just a natural athlete and seems to get herself out of problems so, whether she is back, forward or wide she copes with all situations. It's as if she wants to be a winner."
Update your news preferences and get the latest news delivered to your inbox.