ZENYATTA could yet start an odds-on favourite to win her second Breeders' Cup Classic at Churchill Downs, as the connections of American racing's megastar hinted that retirement plans could be shelved for the second year running if their champion wins on Saturday.

Having been 4-1 joint-favourite with Lookin At Lucky last week, Zenyatta fever has taken hold, and the mare was on Wednesday cut to 2-1 by several firms, who reported further floods of money for the unbeaten mare.

These include Coral, whose on-the-scene spokesman Simon Clare said: "The gamble on Zenyatta continues to grow in size and intensity, just as the hype and hysteria surrounding the undefeated filly threatens to go stratospheric here in America.

"We are now 2-1 having been 7-2 two days ago, and there isn't a cat in hell's chance that she will start any bigger on Saturday.

"If the American betting public bet with their hearts on Saturday, andthey surely will, Zenyatta will start odds-on on the PMU and just watch her odds collapse with the UK bookies."

Zenyatta looked in great shape on Wednesday when exercising on the Churchill Downs dirt, her exercise rider Steve Willard saying: "She loves this track, and she loves the dirt.

"She drives off it. She could not be training any better and is maintaining a good mental capacity. We want her to be nice and calm. The only time we want her to be in a hurry is when she's turning for home."

The Breeders' Cup Classic is due to be Zenyatta's final race - as it was last year, after which she was 'unretired' - but joint-owner Ann Moss said: "I don't think last, ever. It's not a commitment, but we've always gone race to race and she's having such a good time.

"I think horses tell you when they want to do something different, and if you saw her today it didn't look as though she does."