Yes, she loves to clown around and drink Guinness, but this lady is all business on the racetrack.

A late starter, the imposing six year old mare named Zenyatta had her first race on Thanksgiving 2007 and has now beaten 112 other horses and has 19 victories and no defeats. It is a record being called the longest streak in thoroughbred racing by a horse competing at the sport’s pinnacle.

This Saturday, Zenyatta defends her title in the Grade I Breeders’ Cup Classic at Churchill Downs, facing up to 14 rivals that could include the Preakness winner Looking at Lucky and top older horses like Blame and Quality Road. Yet Zenyatta lost out last year to another distaff named Rachel Alexandra in the voting for Horse of the Year. Rachel Alexandra had a dream season in 2009, becoming the first filly in 85 years to win the Preakness Stakes. She also won the Haskell Invitational and Woodward Stakes against the boys. But her campaign in early 2010 was disappointing and she was retired without meeting Zenyatta.

Whatever happens, Zenyatta’s owners will retire her after Saturday’s showdown. Even if you’ve never been a thoroughbred racing fan, I recommend tuning in this one on ESPN. If she wins, there’s talk that she could challenge Secretariat’s hold on the American imagination as the greatest super horse of all time. Even if she loses, it will be a long time before racing sees two giants of the female gender like Zenyatta and Rachel competing for the ages. As a marketer, I salute the trainers of both Zenyatta and Rachel Alexandra for brilliantly showcasing these superstars and retiring them at their peak. The result has been an inspirational storyline in a time of national doubt.