By casting doubt on the health of his Ballydoyle string, Aidan O’Brien put a cat among the pigeons before Sunday’s leg of the Irish Champions Festival, but still managed a Group One Curragh double highlighted by Scandinavia’s Comer Group Irish St Leger success.

The outstanding 4/11 favourite led home a 1-2-3 for O’Brien which came on the back of a sweeping success for Sun Goddess in the Moyglare Stud Stakes.

With his sons Joseph and Donnacha saddling the winners of the two other Group One prizes up for grabs it turned into a red-letter day at the Curragh for the family, who wound up winning six of the eight races.

It means the prospect, however, of O’Brien’s comments being parsed for meaning for much of the emerging autumn campaign.

Darkness Falls was an impressive winner for the sport’s dominant figure at Leopardstown on Saturday, but Constitution River could only finish third to Hotazhell in a dramatic Irish Champion Stakes while none of his four runners hit the frame in Doncaster’s St Leger.

O’Brien said on TV that his team have been coping with a “very low-grade infection” in recent months, perhaps explaining why Sun Goddess was his only top-flight success through August. He also reported that the Derby winner Christmas Day coughed a number of times on the way to the Leger start.

“It’s one of those things. It’s been there a couple of months, we’re dealing with it, you have to keep it going. No horses ran until we were 100 per cent sure but sometimes when you travel it brings little things to the fore. There’s never any harm to them after but obviously there’s little things lurking there and we have to be careful,” he said.

“Anyone who has horses knows about these things. We blood so much. You see when there’s a spike in the blood and the SAA level goes right up and then disappears down. Obviously, there’s a little thing there which we can’t put our finger on where it is or what it is, but it will work through, it always does.

“It’s just there at maybe a delicate time but every week that goes by will help them through and the three-year-olds at this time of year are usually the ones who are more prone to it because they have been trained for the classics and would have had a tough year up to then,” he said.

If that presented a quandary to punters it didn’t prevent Sun Goddess winning in style and Scandinavia winning the Leger in characteristic stolid form, both as odds-on favourites.

Scandinavia, the season’s outstanding stayer, beat the pace-forcing Queenstown by two lengths with another stable companion Jan Brueghel in third.

“He’s a great horse. He just has an unbelievable amount of stamina. He’s a big high cruiser and we were delighted to have Queenstown there today to keep going along,” O’Brien said. “He just goes along there, lazing along. He really only kicks in after a mile-and-six which is very unusual.”

Sun Goddess is a very different proposition and has a range of options to expand her Group One CV.

“She looks a freak. Everything she’s done has been freakish,” said O’Brien. “She’s a very big filly and you’d imagine looking at her she should be a way better filly next year. She’s just natural really, very unusual.”

The new note of unpredictability, however, looked to be stamped on the Goffs National Stakes where the outsider Florida Bay did the best of a Ballydoyle trio by finishing third behind a Joseph O’Brien 1-2.

Ultimately, there was barely a second as Folsom Blues shot six lengths clear of the favourite Monogram to deliver Joey Sheridan a second top-flight career success. He landed the Prix Du Cadran in 2020 on Princess Zoe.

It completed a profitable weekend for the trainer whose Highwayman beat Enceladus for a Doncaster Leger 1-2.

“It was a great ride, very cool and executed perfectly. I suppose the Dewhurst would be an obvious stepping stone. We had America in the back of our mind as well, before this race. I suppose it would be along those lines,” O’Brien said.

“He’s a good horse. Dropping him back to six was probably a big thing to ask him [last time when runner-up to Sun Goddess in the Phoenix] and he ran great. He loved coming back to seven.”

The trainer ended the 13th Champions Festival with a final day hat-trick, completed by the Oaks winner Thundering On returning to action with a stylish success in the Group Two Blandford. Ryan Moore was on board her and also Star of State, who duly justified 1/5 odds in the lucrative Tatts Sales contest.

“The Arc is an obvious target (for Thundering On) but Ryan just said she has plenty of pace and he’d be happy at 10,” O’Brien said. “But I like the look of the Arc.”