The Aidan O'Brien-trained Blenheim Palace proved very tough when making the breakthrough at pattern level in the Diamond Stakes at Dundalk this evening.

The Galileo colt had been placed three times in Group 3 company this season before finally securing a race at the same level on his all-weather debut.

Donnacha O'Brien made the running on the 5/1 shot but he was headed going to the furlong pole by Numerian

Blenheim Palace found plenty for pressure, and despite wandering slightly, got his head back in front in the dying strides for a head victory.

The stewards had a look at the finish with Fresnel who eventually dead-heated for fourth, getting slightly hampered a couple of times but the result was unaltered.

4/6 favourite Mootasadir proved a major disappointment, fading in the closing stages to finish last.

Donnacha O'Brien said of the winner:- “He's a little bit idle, that's why he had the blinkers on, but once the horse came to me and I got stuck into him he found plenty for me.

“The surface didn't seem to be a problem for him anyway. He deserved to be bang there and it's nice to get a big win into him.”

The win moved O'Brien back to within two of Colin Keane in the title race after a double earlier on the card for his rival.