Windsor Palace caused a huge upset by holding off his esteemed stablemate St Nicholas Abbey to clinch the High Chaparral European Breeders Fund Mooresbridge Stakes at the Curragh.
Trainer Aidan O'Brien landed this Group Three prize for the past two seasons with proven top-class performers Fame And Glory and So You Think, and multiple Group One winner St Nicholas Abbey was the 2-5 favourite to complete the hat-trick.
Having signed off his 2011 campaign with a brilliant performance in the Breeders' Cup Turf and finished a narrow second in the Dubai Sheema Classic two months ago, this appeared to represent an ideal opportunity for the five-year-old to find the target.
Joseph O'Brien, fresh from his sparkling performance in the saddle on Camelot in Saturday's 2000 Guineas at Newmarket, was happy to sit third as stable companions Windsor Palace and Robin Hood set a strong gallop.
The two of them had opened up a big lead on the rest of the field rounding the home turn, but both O'Brien and Johnny Murtagh on second-favourite Sharestan were happy to let them go.
However, a couple of furlongs later it was evident that the front pair were not stopping and although the market principals were making good late ground, it proved all too late.
Windsor Palace (66-1) and Colm O'Donoghue passed the post with a length in hand over St Nicholas Abbey, with Sharestan grabbing third from Robin Hood.
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."
A stewards' inquiry was held into the running and riding of St Nicholas Abbey, and after viewing the video of the race and considering the evidence, the officials noted the explanations offered by both trainer and jockey with reference to the horse being unsuited by the ground.
Sharestan's trainer John Oxx is eyeing a tilt at the Irish 2,000 Guineas with the potentially exciting Takar after he took the Dylan Thomas European Breeders Fund Tetrarch Stakes.
A confident Murtagh still had the 5-4 favourite positioned last heading inside the final furlong but after angling him out wide, Takar soon picked up and struck the front, scoring by a cosy length and a quarter.
Coolnagree did not have the best of passages but finished off strongly to grab the runner-up spot.
Oxx said: "He won well considering he's had a few setbacks. He was laid-up for a short while after his win in October and then for another three weeks in February.
"He's done well to get here but I couldn't say he lacked for fitness.
"I was worried about the heavy ground but I'd suppose it wasn't the toughest field.
"He's a talented fella and we'll try him at a mile now with the Irish Guineas likely to be his next run."
Gossamer Seed gave her younger rivals a sound beating in the Canford Cliffs European Breeders Fund Athasi Stakes.
John Joseph Murphy's 9-1 chance was conceding the best part of a stone to each of her four adversaries, but easily pulled clear in the hands of Shane Foley to register a four-and-three-quarter-length victory over market leader Bulbul.
Murphy's son, George, said: "This filly will probably go for another stakes race in a month and then she'll likely get a break.
"We'll try to make the most of any opportunities for her on soft ground."
Foley went on to complete a notable double as Mick Halford's Ondeafears (6-1) ran away with the Newbridge Credit Union Handicap.
Jim Bolger's Move To Strike looks sure to go on to better things after getting off the mark at the second attempt in the Alfred Nobel European Breeders Fund Maiden.
The juvenile was sent off the heavily supported 4-6 favourite on the strength of his debut third at Leopardstown last month and he was never in any danger as he quickened right away under Kevin Manning to score by nine lengths from Slope.
Bolger said: "He was impressive and he came on from his run at Leopardstown. We'll play it by ear with him now."
Wrekin Rock (7-1) collected the Keadeen Hotel Wedding Specialists Handicap for Jim Gorman and Michael Hussey.
Gorman said: "He would have been a good second but for falling at Punchestown.
"He's been on the go a long time now and he might have a rest. He could have some May grass and come back for Galway.
"There's a four-year-old hurdle on the Monday but he wouldn't go on the firm."
The David Wachman-trained Singing Bird (16-1) made a winning debut under Billy Lee in the P.G.Duffy & Sons Citroen Maiden.