Aidan O'Brien yesterday gave the remarkable Giant's Causeway a bullish vote of confidence to take on the best American dirt horses in the Breeders' Cup Classic and, intriguingly, raised the possibility of giving the colt two more runs before heading to Churchill Downs.

The Ballydoyle trainer confirmed Ascot's Queen Elizabeth II Stakes as Giant's Causeway's likely next target but added: "There is a possibility he could run in the English Champion Stakes, too. He was mad keen this morning and he is taking his races so easily."

The latest "easy" race for the Storm Cat colt was Saturday's Esat Digifone Irish Champion Stakes, which he won by half a length from the fast-finishing Greek Dance. That was his fifth Group One victory in a row and the raucous, almost National Hunt-like, reception Giant's Causeway received from the large crowd confirmed his popularity with the Irish racing public.

Only Mill Reef has a comparable winning sequence in the top rank since the pattern race system was introduced in 1971, but he needed two seasons to rack it up. Giant's Causeway has needed just three months, and the five Group One, thrown in with last year's Prix de la Salamandre, echoes the record of the legendary Nijinsky.

Giant's Causeway isn't finished yet, however, and on November 4th it could be the American public who will stand in awe of his fantastic durability when he contests the Breeders' Cup Classic on dirt. O'Brien yesterday was extremely confident of his champion's ability to cope with a new surface.

"I don't think the dirt will bother him. His father and mother were dirt champions, and the others cannot go fast enough because he has such great tactical speed," O'Brien said.

The trainer then added: "It might not be a horse that beats him in America but circumstances. If he didn't travel well over there, for instance. But he is a great horse who is still improving. Maybe I shouldn't say it but it's a big shame that Dubai Millennium is retired because he would have suited our horse perfectly. All he wants is a lead. As you saw at Leopardstown, they can't go fast enough for him."

Sure enough the reviews that Giant's Causeway picked up at the weekend were many. "A very strong horse," offered Sheikh Mohammed, whose Best Of The Bests ran a fine race in third after challenging Giant's Causeway for much of the straight. "A very special horse," came from the winner's owner, Michael Tabor, and "that puts him right up there with the greats", from rider Michael Kinane.

It was O'Brien's immediate post-race comments that encouraged even further hope for a tilt by Giant's Causeway at the top Americans on their own patch.

"We've only seen the tip of the iceberg with this horse. He's only playing with these other horses. He likes a battle and never wins by far but he finds it so easy," he said before offering a comparison with his hurdling champion, Istabraq. "The two of them are the clearest horses in their wind that you'll ever find. The just don't blow, no matter what you do with them."

Significantly, however, the Godolphin spokesman Simon Crisford said: "We'll meet him again at Ascot, and with something different." According to Saeed Bin Suroor that something different is likely to be Bachir, the last horse to beat the Irish champion, in the Irish Guineas, or China Visit.

John Murtagh had a slightly checked run in the big race on Greek Dance, but there were no such problems with Namid in the Group Three Flying Five and John Oxx's colt, returning from a knee chip operation, earned himself a tilt at the Prix de l'Abbaye.