Aidan O'Brien begins playing his Derby chips with a vengeance when Ruler Of The World lines up for tomorrow's Chester Vase but Battle Of Marengo is still expected to wind up his Epsom ace if successfully coming through Sunday's Derrinstown Stud Trial.

Leopardstown’s Group Two is historically O’Brien’s preferred route to the Blue Riband over the years and Battle Of Marengo will follow a tried-and-trusted pattern when he lines up at the weekend.

Like his sire, Galileo, who won the Ballysax and the Derrinstown before graduating to Derby glory at Epsom in 2001, Battle Of Marengo has already scored in the Ballysax and he heads a half-dozen strong Ballydoyle entry among the 12 hopefuls left in the weekend highlight after yesterday's forfeit stage.

High Chaparral also took the Leopardstown road to Derby success in 2002 as did other star Ballydoyle names such as Fame And Glory in 2009. He wound up finishing second to Sea The Stars and it is another impressive Guineas winner, Dawn Approach, who currently dominates the Epsom betting.

However, the strength of Jim Bolger’s 2013 classic crop is illustrated by the appearance of another unbeaten Group One star, Loch Garman, among the Derrinstown entries, alongside another highly rated stable companion, Trading Leather.

Both of those colts also remain in Sunday’s Poule D’Essai Des Poulains, alongside another Bolger entry, Leitir Mor. However, the trainer has indicated the Derrinstown is a likely option for both.

The O’Brien and Bolger powerhouse yards dominate the look of this year’s Derrinstown, a race O’Brien has won nine times and Bolger three, including last year with Light Heavy.

Ground conditions at Leopardstown were“firm” yesterday ahead of a card that also includes both the Amethyst Stakes and the Irish 1,000 Guineas Trial.