Battle of Marengo secured an impressive victory in the PW McGrath Memorial Ballysax Stakes at Leopardstown.
The Aidan O'Brien-trained horse was an 8-13 favourite for the first recognised Derby trial of the flat season.
Ridden by the trainer's son Joseph, Battle of Marengo beat Sugar Boy by a length and three quarters, with Imperial Concorde finishing third.
Rawaaq secured a comfortable win in the Leopardstown 1,000 Guineas Trial.
It was trainer O'Brien's seventh victory in the Ballysax that has previously been won by Galileo and High Chaparral, who both went on to win the Epsom Derby, as well as Yeats.
O'Brien said: "Battle of Marengo is a lovely horse and as a start off, you couldn't be happier with that.
"That was his first time beyond a mile and he wasn't stopping. The ground is real heavy but he's a beautiful mover and he'd prefer real good ground.
"He'll come back here again for the Derrinstown Stud Derby Trial (12 May) before hopefully going to Epsom."
In the 1,000 Guineas Trial, Dermot Weld-trained three-year-old Rawaaq, who was fourth favourite and ridden by Pat Smullen, pulled away from What Style in the final furlong to win by a length and a quarter, with Snow Queen finishing third in heavy conditions.
Smullen said: "She's a nice filly and all last year she was running consistently well. What she might lack in a little bit of class she has in heart."
Fort Knox, ridden by Johnny Murtagh, won the 2,000 Guineas Trial.