Fascinating Rock has reversed recent form with Found to claim top honours in the Tattersalls Gold Cup at the Curragh.
The Dermot Weld-trained Fascinating Rock had beaten Aidan O'Brien's subsequent Breeders' Cup Turf heroine in last season's Champion Stakes at Ascot, but Found gained her revenge when the pair met in the Mooresbridge Stakes three weeks ago.
Found was the 8-15 favourite to confirm that form in this Group One contest, but Weld's inmate showed improvement from his first run of the year and galloped on strongly to score by three and three-quarter lengths in the hands of Pat Smullen
Success Days, who split Found and Fascinating Rock when runner-up in the Mooresbridge, finished a close third, having raced alone against the stands' rail in the straight.
Smullen, who would go on to record a treble, said: "He's a very good horse. We were always confident he was going to improve for his last run.
"We were very pleased with his work heading into the race.
"He's a horse who is only maturing now, but he's a horse who needs ease in the ground.
Earlier, Beacon Rock led from start to finish to claim victory in the Airlie Stud Gallinule Stakes.
The Group Three contest has been dominated by O'Brien in recent years, with the Ballydoyle maestro having saddled 13 of the last 19 winners, and he fielded three of the five runners this year.
Beacon Rock was the 9-10 favourite, having run creditably in the Ballysax Stakes and in the Derrinstown Stud Derby Trial, and soon dominated under Ryan Moore.
The Weld-trained Foxtrot Charlie tried to throw down a challenge in the straight, but Beacon Rock found plenty for pressure to score by two lengths.
Santa Monica, the only filly in the line-up, finished strongly to grab the runner-up spot.
Speaking after, O'Brien said: "He's a tough horse and kept responding.
"Ryan was left alone in front and gave him a very good ride. He was only doing what he had to do.
"We'll have a good look at Ascot with all those horses and he'll get a mile and a half."
In the opener, Van Der Decken made a smart start to his career with a comprehensive victory in the Elusive Pimpernel EBF Maiden.
The six-furlong contest went to O'Brien's multiple Group One winner Air Force Blue 12 months ago and the Ballydoyle handler was this time responsible for the 2-1 favourite in the unraced Churchill, who finished third.
After having been sent off a heavily-backed 6-1 shot, Van Der Decken was prominent throughout in the hands of Wayne Lordan and hit the front inside the final furlong.
Runner-up Magnification and Churchill came home well, but the Paddy Twomey-trained winner held them at bay by two and a quarter lengths and a head respectively.
Speaking after, Twomey said: "That's my first two-year-old winner. Wayne gave him a lovely ride and everything seemed to go OK.
"I was a bit worried about the ground coming here as I think he'll like better ground. I'm thrilled with him.
"He's entered in the Phoenix Stakes (Curragh, August 7) - we'll see where we go.
"I've never had a runner in England before, but I might consider going across the water (for Royal Ascot). We'll take him home and see how he is.
"Wayne said he thinks he'll get further."
Jet Setting takes 1,000 Guineas glory
Creggs Pipes ran out an authoritative winner of the Irish Stallion Farms EBF 'Habitat' Handicap.
Andrew Slattery's filly was a 7-1 shot to follow up her course-and-distance victory three weeks ago and did so in some style in the hands of Pat Smullen.
Champagne Or Water finished second, beaten a length and three-quarters.
Following the earlier victories, Smullen completed his treble aboard the Weld-trained Maneen in the Joanna Lumley 70th Birthday Celebration Handicap.
Jennies Jewel, last seen finishing second in a Grade One over hurdles at Punchestown, made a successful return to the Flat game with a one-length success in the Irish Tatler Handicap.
Trainer Jarlath Fahey said of the 7-4 favourite: "She has been covered by Presenting and is due to be scanned in a week's time.
"It's a possibility she might go to France for the Champion Hurdle but if she's in foal and we want to mind her.
"She might go for the Ascot Stakes as long as the ground is not quick."
Team Ballydoyle at least put the seal on an indifferent afternoon as The Major General (3-1) took charge in the concluding Irish Stallion Farms EBF Maiden.