Wearing a pink, cropped saddle which revealed her dark brown skin and haunches, Zenyatta left little to the imagination and likely won herself a whole segment of fans.
"It might not sound very progressive, but when it comes to female athletes, sex sells way more than victories," said Mark Pynor, a sports branding consultant. "Anna Kournikova is much more famous than someone like Kim Clijsters is. Natalie Gulbis is more popular than I don't even know if I can name another female golfer."
And in losing for the first time, Zenyatta also showed a vulnerability that is attractive in female athletes.
"A lot of guys are turned off by a girl they think can beat them at sports," said Pynor. "It's cool if she's into sports, but they don't want to lose to a girl or be with a girl who is seen as too macho."
With her profile now higher than ever, Zenyatta is expected to weigh her endorsement offers and possibly even decide to give up on being competitive to focus on becoming a full-time pitchmen like Danica Patrick.
John Sherriffs, the mare's trainer, says he has never been around a horse who is so image conscious.
"Just watch her around the cameras," he said. "It's rare to see her take a dump when there are cameras nearby. That's very rare in the ad biz."