Sovereign and Padraig Beggy have caused an upset in the Irish Derby, giving trainer Aidan O'Brien a 13th success in the Classic at the Curragh.

The stands almost fell silent as the 33-1 shot crossed the line six lengths ahead of stable companion Anthony Van Dyck, the Epsom Derby winner.

The win was a second long-priced Derby winner for Beggy who won at Epsom on 40-1 chance Wings Of Eagles two years ago.

Sovereign was expected to be one of the lesser lights of O'Brien's five runners and made the running with stablemate Norway.

Broome, one of O'Brien's better-fancied contenders, was slowly away and the two pace-setters soon built up a big lead.

The pair was eight lengths clear with four furlongs (800m) to go and did not come back to the field as might have been expected, with Sovereign, who was only 10th at Epsom, never looking like being caught.

Anthony Van Dyck (5-4 fav) was 2-1/2 lengths ahead of third-placed Norway (16-1), with Madhmoon just behind in fourth.

"They were all there and they were all trying their best," O'Brien said.

"It was all very straightforward. Everyone knew Padraig was going to lead and Seamus (Heffernan, on Norway) was going to follow him.

"The race maybe unfolded a little bit unusually. What happened was that Donnacha's (O'Brien, on Broome) horse missed the break, he came out very slow and everyone might have expected him to fill the third position."

Ladbrokes slashed the price of Sovereign in half for the St Leger, going 10-1 for the Doncaster Classic.

Beggy, who spent some time riding in Sydney until 2014, said the Irish Derby meant more than Epsom.

"I'm over the moon," he said.

"This would be more important to me (than the Epsom Derby) as an Irishman, the Irish Derby.

"I served my time with Kevin Prendergast just up the road and this was the race that you grew up wanting to win. That was my main aim as an apprentice.

"I'm just very, very lucky that I've won the English Derby and the Irish Derby. That is down to a big group of people, but I would have to say mainly Aidan O'Brien to put me on.

"I just got into a lovely, comfortable rhythm and I felt like I could go quicker all through the race. My horse really enjoyed it here, a big galloping track.

"I just said keep him organised to the line now, you've won. Dreams come true!"