Battle Of Marengo has laid down an early marker for the Epsom Derby with a determined triumph in the Ballysax Stakes at Leopardstown.

A winner of three of his four starts as a juvenile, rounding off his campaign with victory in the Beresford Stakes at the Curragh, Battle Of Marengo was sent off the 8-13 favourite to give trainer Aidan O'Brien a seventh victory in the first recognised Derby trial of the Flat season.

Ridden by the trainer's son Joseph, the three-year-old moved well for the first half of the 10-furlong (2000m) journey but was being pushed along from the home turn.

For a moment it appeared Sugar Boy would make a real race of it, but once O'Brien picked up his whip, Battle Of Marengo went about his business in fine style, soon asserting to score decisively by a length and three-quarters.

Battle Of Marengo is as short as 8-1 (from 12-1) with bookmakers to emulate former Ballydoyle greats Galileo (2001) and High Chaparral (2002), who both won the Ballysax en route to glory in the premier Classic at Epsom.

"Battle of Marengo is a lovely horse and as a start-off, you couldn't be happier with that," Aidan O'Brien said.

"That was his first time beyond a mile and he wasn't stopping.

"He'll come back here again for the Derrinstown Stud Derby Trial (May 12) before hopefully going to Epsom."

O'Brien conceded he was "fighting time" in his bid to get stablemate Kingsbarns to the Derby after a setback which cost him nearly two weeks work.

Already ruled out of the 2000 Guineas, Kingsbarns could still make a Derby trial but the trainer said any lead-up race would be left as close to the June 1 Epsom showpiece as possible.