Aidan O'Brien hailed Delacroix's "very unusual" quality after the favourite accelerated away in the Royal Bahrain Irish Champion Stakes. Christophe Soumillon produced the 2-1 favourite to lead with two furlongs to gallop at Leopardstown and the pair had too much speed for minor medallists Anmaat and Royal Champion.
The performance completed a memorable day for O'Brien, who scooped the Betfred St Leger at Doncaster with Scandinavia and was adding to two earlier track strikes with super sub Christophe Soumillon.
O'Brien was present to watch Delacroix, who made smooth headway and kept on strongly for pressure up the nearside rail.
"He's some horse to quicken," he said. "It was an even, strong run race. He (Soumillon) was very confident on him and when he said go he fairly took off.
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"I don't think I've ever seen a horse do that at Sandown and he did it again today. It was very unusual.
"He ran there, it was whoosh, gone. It was over in two strides. I'd like to go back and look at it again."
It was Delacroix’s second Group One of the season, his display coming several months on from the Coral-Eclipse at Sandown. Runner-up Ombudsman then gained his revenge in York's Juddmonte International.
But O'Brien reasoned: "We knew York was only a sprint down the straight really.
"I don't know if he will run again. He has all the options - they could do anything they want with him. He's a hardy customer."
By the time Scandinavia starred in the final English Classic with Tom Marquand in the saddle, O'Brien had seen Benvenuto Cellini work his way to the head of next year's Derby market.
Like the St Leger, it is sponsored by Betfred and the firm make him a 10-1 chance after a he was authoritative in the KPMG Champions Juvenile Stakes.
The white-faced chestnut had been as big as 25-1 before he scooted five lengths clear of Hardy Warrior.
"Christophe said he feels like a French Derby horse," O'Brien added, the race run over approximately ten furlongs compared to Epsom's twelve.
"He can go again this year, the Futurity or one of the French races, and then start in the Derby trials next year."
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