Rachel Alexandra loses by a neck

The horse race that thoroughbred fans want most was not wiped out at Churchill Downs on Friday.

Jess Jackson, majority owner of Rachel Alexandra, the 2009 horse of the year, said his 4-year-old mare was still coming back from a six-month layoff. Her loss by a neck, in a thrilling stretch duel with Unrivaled Belle in the $418,800 La Troienne, the sixth race on Kentucky Oaks Day at Churchill Downs, was not unexpected, he said.

Rachel has raced twice this year and lost twice.

“I’m not disappointed in either race,” Jackson said. “She is still not 100% back. She could be 10 lengths better than she was today.”

Jackson said his prize mare came out of the race healthy and that there was no reason that the much-anticipated Rachel-Zenyatta matchup could not still happen.

“She’s not going to retire, I can tell you that,” Jackson said. “When she can finish in 12 seconds flat, then we’ll know she is back.”

Rachel Alexandra was voted horse of the year in last year’s racing Eclipse Awards, and by that time, 5-year-old star mare Zenyatta had retired unbeaten. Zenyatta’s apparent grand finale had been her thrilling victory in the $5-million Breeders’ Cup Classic in early November at Santa Anita. No filly or mare had won that race before.

There had been indications that Zenyatta owners Jerry and Ann Moss had been disturbed by the wide margin of victory in the Eclipse voting. In January, they announced that Zenyatta would run for another year. An April 9 race at Oaklawn Park in Hot Springs, Ark., that included both horses fell through when Rachel lost a tuneup -- coincidentally to a horse trained by Zenyatta trainer John Shirreffs.

A date for a matchup is uncertain. Zenyatta is likely to run at the Vanity in June at Hollywood Park. Jackson said he would make no quick commitments for Rachel’s next race.

bill.dwyre@latimes.com