Joseph O'Brien's Iridessa bounded clear in the final furlong to make an impressive debut in Killarney's median auction race for juveniles.

The daughter of former Epsom Derby winner Ruler Of The World was the only filly in the field and looked to have a daunting task against three former winners and Cardini who was fifth in the Listed Chesham Stakes at Royal Ascot.

Cardini went off 4/5 favourite for Aidan and Donnacha O'Brien and set out to make all over this extended mile.

However, Iridessa made good headway to challenge under two furlongs out and picked off the favourite approaching the final furlong under Seamie Heffernan.

The 20/1 shot went right away from Cardini in the final 100 yards to score by four lengths.

Seamie Heffernan said: "Joseph gave me the impression he liked her and I'd be inclined to agree!

"I haven't ridden many easier winners around here and she was by Ruler Of The World, which we had (at Ballydoyle), and she's definitely bred to be above average. I wouldn't mind riding her again and she's real nice.

"Aidan's (Cardini) is a lovely, lovely horse but is still immature and is going to take a few runs and is going to end up being a Group horse."

This was a first winner for the sire Ruler Of The World.

Additional reporting by Thomas Weekes