Windsor Palace sprang a big surprise by winning the High Chaparral European Breeders Fund Mooresbridge Stakes at the Curragh.
Along with Robin Hood, the 66-1 winner was in the race to act as pacemaker for stablemate St Nicholas Abbey but turning in the pair were ten lengths clear of their rivals.
Sharestan initially led the pursuit and St Nicholas Abbey picked up late in the day to reel him in for second but this was Windsor Palace's day and he held on by a length under Colm O'Donoghue.
Robin Hood, who helped set the ferocious early pace, was fourth.
Winning trainer Aidan O'Brien said: "He (Windsor Palace) had a good run here the last day (third behind Excelebration) and he's a soft ground horse.
"We knew St Nicholas Abbey wasn't a heavy ground horse, everyone knows that. Joseph just let him find himself there and it was his first run back after Dubai.
"He (St Nicholas Abbey) ran a lovely race and we're delighted with him. Sometimes it happens, they don't get through that ground, that's the way it is, that's racing. We are happy with the horse and hopefully he will come forward from it.
"You'd be happier if he won but he didn't, but there's always another day. The Coronation Cup will be next for him."