America at Large: It was easy to spot Aidan O'Brien at Lone Star Park yesterday. He was the one without the cowboy hat. "They couldn't get one to fit me," joked the Tipperary-based trainer.

There were 12 European-based horses stabled in the Quarantine Barn on the Lone Star backstretch yesterday, and five of them were O'Brien's. Only New York trainer Bobby Frankel, with six, has more horses entered in the 21st edition of the Breeders' Cup races which will be run on the Texas oval Saturday afternoon.

O'Brien has had 24 runners in the Breeders' Cup in the past six years and has come home with a winner in each of the last three. Johannesburg won the Juvenile in 2001 while High Chaparral took the Turf 12 months later and dead-heated for the same race last year.

The trainer had to spend 12 minutes in a cold sweat while the stewards pored over a photo finish, attempting to separate the Irish horse from Johar. In the end they could not and declared the first dead heat in Breeders' Cup history.

By almost any standard 2004 has been a disappointing campaign for O'Brien. Back in May at Longchamp, his three-year-old Antonius Pius appeared to be a runaway winner in the Grade One Poule d'Essai des Poulains. With 150 yards to run, the horse suddenly veered to his right and crashed into the rail, and by the time rider Jamie Spencer was able to regain control he had faded to fifth. An even more disheartening turn of events ensued in August when O'Brien brought Powerscourt across the Atlantic to run in the Arlington Million in Chicago. Powerscourt won by a length and a half, but had lugged in the stretch and, following a steward's inquiry, was disqualified and placed fourth.

"He drifted across the track and the horse on his inside drifted out, and we interfered with the third or the fourth horse," recalled O'Brien yesterday. It wasn't all Powerscourt's fault, but at the end of the day it was the stewards' decision and we lost the race. It was just one of those things."

Seeking redemption, O'Brien has brought both Powerscourt and Antonius Pius to Texas for Saturday's World Thoroughbred Championships. Powerscourt will be seeking to become the heir to High Chaparral in the Turf, while Antonius Pius will take on 13 other competitors in the Breeders' Cup Mile.

O'Brien also has Yesterday, a four-year-old filly whose last win came at Leopardstown nearly two years ago, entered in the Filly & Mare Turf race, along with a pair of lightly-raced two-year-olds - Scandinavia, who broke his maiden at the Galway Races on July 31st, in the Juvenile, and Mona Lisa, winless in three starts, in the Juvenile Fillies.

It is fair to say that O'Brien's best hope lies in Powerscourt. The Sadler's Wells colt drew the inside rail at yesterday's post position draw, and was promptly established as second-favourite at 3 to 1, behind even-money choice Kitten's Joy, by track handicapper Rick Lee.

"We're hoping," shrugged O'Brien. "The horse is in good form. Obviously, it's a different world over here, halfway across the continent.

"They're all fast-ground horses, but our horses are used to running on softish ground, so whatever happens, happens," said O'Brien, who didn't sound particularly hopeful.

"He's not going to be an easy ride, because once he gets on the lead he has a habit of wandering left or right, but if he can get there, he's capable of doing anything."

Of the rest of the Irish contingent, Yesterday is the morning-line third-choice at 6 to 1 behind 8 to 5 Ouija Board and 7 to 2 Light Jig in the Filly & Mare Turf, while Scandinavia and Mona Lisa are outsiders at 15 to 1 in their respective two-year-old races.

By bringing together the world's best, the Breeders' Cup tends to be almost by definition a crapshoot for all concerned. "It is, but I think that's great," said O'Brien. "The Breeders' Cup is unique in that respect, but I think it's great that you can bring together the best horses in Europe and America. It's a great spectacle for everybody."

Spencer, though relatively inexperienced in Breeders' Cup competition, will have the mount on all five of O'Brien's horses. "Jamie's going to ride all of them," said the trainer. "He's going to be riding in a jockeys' challenge over the next couple of days, so he should know the track by Saturday."

Situated in the thriving metropolis of Grand Prairie, midway between Dallas and Fort Worth, Lone Star is by far the youngest venue ever to host a Breeders' Cup meeting. Its 20 predecessors have been conducted at more hallowed and venerable racing shrines around the US and Canada, but, like most first-time visitors to the facility this week, O'Brien was pleasantly surprised to discover that, at least, it has the look and feel of an authentic racetrack.

"We wouldn't be used to the dirt, but while turf is different from racetrack to racetrack, when you come right down to it, grass is grass," said O'Brien. "We work on artificial surfaces back home, so we're hoping."

His hopes Saturday rest primarily with Powerscourt, but, said O'Brien, "the two-year-olds are in good form, as are Antonius Pius and Yesterday, but obviously it's a lot to ask of any of them. We'd be delighted if they run well."