Aidan O'Brien's Gold Cup hero Leading Light made the perfect return to action in the Palmerstown House Estate Irish St Leger Trial Stakes at the Curragh.

Given a break since his efforts at Royal Ascot, last year's Doncaster St Leger winner was shouldering 10st against a useful field, but in the end just needed to be kept up to his work to win by Joseph O'Brien after hitting the front a furlong out.

The front-running Shu Lewis missed out for second by a short head as Royal Diamond finished off the race very well, but Leading Light (2-5 favourite) was never in danger once he got to the front and won by a length and a quarter.

The Montjeu colt took his career record to eight wins from 10 starts, having been beaten only on his two-year-old debut and in the Arc.

O'Brien snr, who went on to a four-timer, said: "I'm delighted with that. He's had a good break since Ascot. We let him down well after that and it's nice to get him started back.

"He came here two weeks ago for a canter to wake him up a bit. He should come on nicely from that as he's giving a good blow.

"The (Irish) Leger falls lovely in the second half of the season for him. I don't know where he'll go after that but the main thing is the lads would like him back for Ascot next year. He ran in the Arc last year, but was back a long way. They'll decide where he goes."

Hall Of Mirrors recorded a surprise success for Ballydoyle in the Kilfrush Stud Royal Whip Stakes.

The outsider of the four runners and apparent second string for the O'Brien team behind Kingsbarns, the Seamie Heffernan-ridden four-year-old made every post a winning one, eventually scoring under just hands and heels.

Joseph O'Brien loomed large on Kingsbarns two furlongs out and looked set to win his race when asked to quicken at the furlong pole, but Hall Of Mirrors (13-2) was always seemingly in second gear and won by a snug half a length.

Parish Hall, the 11-8 favourite, had every chance but his challenge proved to be short-lived.

O'Brien snr said: "That was always liable to happen as the other horse is fit. He has had runs and he ran a very good race at Ascot (fifth to Contributer in the Wolferton Handicap). We knew he (Kingsbarns) would get tired today, but he had to run. He came there but got tired.

"The winner is a very good yardstick. He goes a nice pace and he doesn't lie down. He's a tough, hardy gelding.

"Kingsbarns is a horse that's had plenty of things and that's why we've minded him so much. We wanted to get him started and see. It doesn't always go according to the script!"

It was four for Aidan and three for Joseph when Adjusted got off the mark at the fourth attempt in the Irish Champions Weekend Maiden as the 9-4 favourite, coming nicely clear of Sindarban.