There is no wonder Giant's Causeway has been dubbed the "iron horse" for his tough constitution and never-say-die attitude, having rattled off a hat-trick of narrow victories at the highest level.

Aidan O'Brien's colt can make it Group One win number four in the Juddmonte International Stakes at York today.

The Ballydoyle three-year-old started his winning run in the St James's Palace Stakes at Royal Ascot where he beat Valentino by a head.

The son of Storm Cat followed that effort with another head-success, this time beating Kalanisi in the Coral-Eclipse Stakes at Sandown over today's trip of 10 furlongs.

And at Goodwood three weeks ago the powerfully-built individual put up his best performance so far to beat a top-class field for the Champagne Lanson Sussex Stakes.

Always close up in a strongly-run contest, Giant's Causeway led a furlong out and kept on gamely to beat the French-trained Dansili by three-quarters of a length.

Although today's £450,000 contest will be no pushover Giant's Causeway has outstanding credentials and is awarded the nap.

Hemingway can initiate a double for O'Brien by taking the opening race of the three-day Ebor meeting - the Breckenbrough Racing Acomb Stakes.

The son of Spectrum was an impressive winner of a seven-runner maiden on his debut at Galway last month, making all and stretching clear in the straight to score in great style by seven lengths from Avorado.

Last year's Acomb winner was King's Best, who went on to win the Sagitta 2000 Guineas, and a good performance by Hemingway on the Knavesmire could see him take a prominent position in the betting for the Newmarket Classic.

Michael Jarvis' improving colt Marienbard can stake his claims for the Rothmans Royals St Leger with victory in the Group Two Great Voltigeur Stakes.

This good-topped colt has won all his three starts and on his latest outing showed a decent level of form to take a five-runner Listed contest at Haydock Park.

A stronger gallop today will be more in Marienbard's favour and he looks a good bet to keep his unbeaten record intact.

The afternoon's "Showcase" race, the Ladbrokes Knavesmire Stakes, can go to Seek.

Luca Cumani's four-year-old has raced only four times - twice last season and twice this term - and looks just the sort to improve further.

On his reappearance at Pontefract Seek finished an encouraging three-quarters-of-length-second to Just In Time and on his latest start ran well until his stamina gave out.

Back over a mile and a half Seek, who started the campaign on a 4lb higher mark, can overcome his inexperience to land this 18-runner handicap.