Animal Kingdom and Royal Delta were due to leave the United States for the UAE as preparations for the Dubai World Cup next Saturday kick into overdrive.
The 2011 Kentucky Derby hero and the dual Breeders' Cup Ladies' Classic winner spearhead a powerful American challenge that comprises eight horses.
Other notable horses set to take the same direct flight out of Fort Lauderdale, Florida, include Trinniberg and Private Zone.
Trinniberg, the Breeders' Cup Sprint victor, is trained by Shivananda Parbhoo, who saddled Giant Ryan to finish fifth in last season's Dubai Golden Shaheen. Private Zone is from the Doug O'Neill stable that recorded wins in last season's Kentucky Derby and Preakness Stakes with I'll Have Another.
The eight horses will join Dullahan and Little Mike, who both ran at Meydan Racecourse on Super Saturday 11 days ago, to complete the American challenge on World Cup night.
Animal Kingdom and Royal Delta both had their final serious workouts on Monday.
Animal Kingdom worked twice over five furlongs and another over seven at the Palm Meadows training facility in Florida, where he has been based all winter, under the watchful gaze of his trainer Graham Motion.
The time of Animal Kingdom's five-furlong work on grass alongside Howe Great, who beat Dullahan in a Grade 3 race last season, was one minute, 01.78 seconds.
Motion was happy with the work and envisaged no problems with the travel to Dubai.
"Everything has gone by design and he has worked the last three Mondays," Motion told The National. "He is a pretty laid-back horse - he's a cool customer and takes it all in his stride. It is why we are pretty comfortable doing something like this."
Animal Kingdom will be accompanied to Fort Lauderdale by his regular groom David Rock, Motion's long-time assistant, before Alice Clapham picks up the duties in Dubai when the plane arrives tomorrow morning.
The prep races of Animal Kingdom and Royal Delta could not have been more contrasting. Royal Delta, trained by the World Cup-winning Bill Mott, warmed up with an effortless five-length win in a Group 3 at Gulfstream Parkin Florida in February.
A week earlier, Animal Kingdom was beaten in the Grade 1 Gulfstream Park Turf Handicap by Point Of Entry, the Breeders' Cup Turf runner-up.
It was a slowly-run race in which the jockey Joel Rosario made what looked like an audacious mid-race move four furlongs from home that actually compromised Animal Kingdom's chance.
It was the first time that Rosario, who will be in the saddle at Meydan next week, had ridden the five year old and Motion is just glad the mistake was made in America, and not in the most valuable thoroughbred race in the world.
"It was a frustrating performance and he was beaten by a very good horse," Motion said. "The great thing is that Joel has had a run on him now.
"To me Joel moved too early on him and he knows that. If we could do it over again we probably wouldn't and we would like him to have been more handy in the race had we known it would have run so slowly.
"We have patched it up plenty and the Gulfstream race was a learning curve."
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