Rest of Curragh report: The most memorable day of Séamus Heffernan's career will look even better in the history books as the Derby-winning jockey also landed the Group Two Railway Stakes on Lizard Island.
Just as in the big race, Kieren Fallon was on the apparent Ballydoyle number one South Dakota, but, in a four-runner race, that colt met some interference at a critical stage and Lizard Island made all the running to hold off his stable companion by three-parts of a length.
"Kieren rode this horse on his first start at Leopardstown where he missed the break and ran very green. He said there was nothing between the two horses today," Heffernan reported.
It was a ninth win in 11 years in the race for O'Brien, although whether Lizard Island - a 40 to 1 shot for next year's 2,000 Guineas - lives up to the standard of George Washington and some of the others is debatable.
"The conditions are very soft, but these Danehill Dancer colts often handle an ease. We will step him up now," O'Brien said.
The "sprint king" Dandy Nicholls had the two favourites for the Bud Light Stakes, and although Tax Free looked set at one point for a second win of the season in Ireland, he had no answer to the late surge of the 16 to 1 winner Snaefell.
"That's what he wants," said winning trainer Michael Halford. "A fast-run five furlongs where he can come at them at the end. Over six, he gets there on the bridle and doesn't find anything. We've had this race in mind for a while and I was surprised how well he handled the ground."
A frustrating day for Fallon didn't get any better after this race when he was fined €200 for crossing before the marker poles on board favourite Peace Offering.
Nicholls, though, had better luck in the big handicap prize, the €100,000 Scurrys, where the Silvestre DeSouza-ridden Machinist dominated the closing stages to beat Snaefell's stable companion Nastrelli.
"He was okay on the ground and I always thought he was a good horse. That might be handicap company finished for him now," said the English trainer.
Nicholl's son, Adrian, was in trouble with the stewards following the opening handicap won by the Jessica Harrington-trained Jumbajukiba. Nicholls, on Royal Dignitary, got a four-day suspension for an incident just after the start.
The day's other black type event, the Celebration Stakes, saw another Fallon-ridden favourite bite the muck when Chinese Whisper faded from the front outside the distance, leaving the Heffernan-ridden outsider Hard Rock City looking a likely winner.
But he was challenged on either side by the David Wachman pair Danehill Music and Cougar Bay, and although the latter faded, the Danny Grant-ridden filly wouldn't be denied.
The former Group Three winner won out by half a length, and Wachman said: "What more can I say - she likes the mud. This is her track and this is her ground. Danny rides her in her work and gave her a great spin. We will stay in similar Listed or Group Three class."
Harrington, usually more conspicuous at the top National Hunt tracks, added to Jumbajukiba's success in the first when completing a last-race double with Sandymount Earl in the two mile handicap.
The winner also completed a double for John Murtagh, and the success helped him clinch the leading rider award for the three-day festival. Like Heffernan, Murtagh rode three winners, but edged the €1,000 prize on the basis of more third placings.
Significantly, Jamie Spencer made the trip to the Curragh despite not having a ride in the Derby, and he made his mark with a win on board the Tony Martin-trained favourite Arc Bleu in the mile and a half handicap.
• Yesterday's crowd of 28,808 was down over two thousand on last year's figure. However, the attendance bet a new Tote course record of €1,176,770. That compared to €1,044,484 last year.
Bookmaker turnover was up almost a quarter of a million euro to €2,521,595. That included €673,917 on the Derby.