The April 9 Apple Blossom Invitational showdown between 4-year-old filly Rachel Alexandra, the reigning Horse of the Year, and undefeated 6-year-old mare Zenyatta, champion of November's Breeders' Cup Classic. Zenyatta ran her career record to 15--0 last Saturday by romping at the Santa Margarita Invitational at Santa Anita, passing all seven of her rivals in the stretch to win by a widening 1¼ lengths. Just a half hour earlier, however, Rachel Alexandra had come up empty in her first start after a six-month layoff, in the New Orleans Ladies Stakes. Seizing the lead late, she was run down by a 6-year-old mare named Zardana, a stablemate of Zenyatta's, who had been entered by trainer John Shirreffs to test Rachel's mettle. Says Rachel Alexandra's owner Jess Jackson, who backed out of the race at Arkansas's Oaklawn Park the next day, "We now regret we tried to accelerate her training in order to meet the Apple Blossom schedule."