El Salvador gave teenager Donnacha O'Brien a landmark big-race success in the Irish Cesarewitch at the Curragh.

The younger brother of champion jockey Joseph O'Brien, the 16-year-old had only ridden his first winner last month but defied his inexperience with a fine ride on his father Aidan's five-year-old, running in the colours of his mother Anne-Marie.

Burdened with top-weight, O'Brien's 7lb claim proved invaluable as Hidden Universe and Pat Smullen pressed hard through the final furlong, with El Salvador finding plenty for pressure and seeing it out for a length success at 25-1.

Joseph O'Brien finished third on another Ballydoyle contender, Marchese Marconi, with Asbury Boss fourth.

Aidan O'Brien said: "I'm delighted and it's great for Donnacha. It's a hard race to win. He's a tall fellow and is doing his leaving certificate this year. It was a nice, patient ride as the start was a bit messy and he was a long way back.

"He was second in the Queen Alexandra Stakes at Royal Ascot this year, and is a tough horse."

It was a fourth winner for the jockey and a second Irish Cesarewitch for O'Brien snr after Bright Horizon in 2010.