(CNN) -- When Black Caviar lines up at Morphetville, Adelaide, on Sunday in front of an anticipated crowd of 30,000, the Australian wonder horse will carry the weight not only of jockey Luke Nolen but the expectations of an entire nation.
The superstar mare will be bidding for her 20th win from 20 races. If she succeeds, she will have gone one better than the great Zenyatta, who faltered at the 20th attempt.
Black Caviar has already overhauled the marks of such racing legends as Eclipse (undefeated in 18 races) and Nearco (14). Indeed, one has to go all the way back to Kincsem, a 19th century Hungarian racehorse, to find a more impressive streak (although her barely creditable record of 54 wins and no defeats seems safe for the time being).
The Black Caviar phenomenon has gripped a sports-mad Australian public. Of the capacity crowd expected to turn out on Sunday, a good proportion will be wearing her trademark salmon and black silks. The appetite for all things Black Caviar is so great that the state government has arranged free public transport for all those heading to the track.
She will face only a small number of rivals on Sunday. Such is the aura of invincibility surrounding Black Caviar, she typically races against just a handful of other runners. She is currently being quoted by some bookmakers at odds of 1-20 (and no, that's not a misprint) for the Group 1 clash, ahead of last year's Goodwood winner Lone Rock at 14-1.
But despite having beaten the best Australian racehorses of her generation -- including Hay List and Foxwedge, both classy runners in their own right -- Black Caviar remains unproven on the global stage. That is set to change, however. In June, Black Caviar will get the chance to test herself against the best in the world when she travels to England for the Diamond Jubilee Stakes at Royal Ascot.
For Australians, Black Caviar's English endeavor is something of a national cause. But if she has little left to prove to an adoring public back home, a question mark remains over Black Caviar's claims to greatness on the world stage, and that question mark comes in the not-insubstantial shape of a four-year-old bay colt called Frankel.
The only horse in the world with a higher rating than Black Caviar, the inevitable clamor for a showdown between the two best horses in the world is likely to reach deafening pitch should Black Caviar win again on Sunday.
A match race seems unlikely since the two horses prefer to race over different distances: sprints of 1,000 -1,200 meters for Black Caviar; the mile and upwards for Frankel. That hasn't prevented billionaire owner Sheikh Fahad al Thani from sponsoring a £1 million purse should the two horses line up for the Sussex Stakes at Glorious Gooodwood in August.
It would mean a step up in trip for Black Caviar to the mile, over undulating ground that is likely to favor the defending champion Frankel with his huge, all-devouring stride. But with 20 million Australians backing her every furlong of the way, you wouldn't bet against her.
Comparing champions: Black Caviar vs. Zenyatta
The similarities between the two great race mares are evident. Both horses are huge (Black Caviar stands at 16.2 HH while Zenyatta stood at a carthorse-like 17.2 HH), and their hulking frames meant they were each only lightly raced in their early years (larger horses usually take longer to develop).
Zenyatta became a racing -- and sporting -- phenomenon in America, finishing runner-up twice in the Associated Press's Female Athlete of the Year award (once to Serena Williams and once to Lindsay Vonn). Black Caviar's following in Australia is so huge that Channel 7 interrupted the Australian Open tennis semifinal between Novak Djokovic and Andy Murray to televise one of her races.
Zenyatta was named after the album "Zenyatta Mondatta" by British band the Police, who were signed to the record label of her owner, Jerry Moss. Black Caviar was named by one of her owners, Pam Hawkes, who has a taste for the delicacy. It also refers back to the mare's grandmother, Scandanavia.