Odds-on favourite New Approach won the Irish Champion Stakes to seal a Group One double for trainer Jim Bolger.
The Epsom Derby winner, an 8-13 chance ridden by Kevin Manning, was too strong for 50-1 runner-up Traffic Guard.
Mores Wells was third in the 10-furlong contest which failed to enhance New Approach's reputation before a possible tilt at the Prix de l'Arc de Triomphe.
Earlier, stablemate Lush Lashes started a memorable afternoon for Bolger and Manning by winning the Matron Stakes.
New Approach's task in the race, postponed 24 hours because of heavy rain, was made easier when Duke of Marmalade, trained by Aidan O'Brien, was pulled out because of the soft ground.
Beaten into third by Duke Of Marmalade in the Juddmonte International, New Approach was half a length too good for Traffic Guard.
606: DEBATE
He was soon into his running, staying close to early leader Red Rock Canyon. And when Manning went for the jugular on the turn for home, few of his seven rivals could stay near him.
But bookmakers William Hill were not overly impressed with New Approach's performance, easing him out to 10-1 from 8-1 for October's Prix De L'Arc de Triomphe.
Bolger said: "Kevin confirmed that he had bundles in the tank. It was a nice, easy race for him and he should come out of it well.
"He's in the Champion Stakes at Newmarket, he's in the Arc and he's also in the Breeders' Cup Classic. He'll probably run in two of those three."
Meanwhile, Lush Lashes won her third Group One of the season when holding off Nahoodh by a neck.
She was always prominent in the one-mile Matron Stakes. And once Manning pressed the button as the pair straightened for home, the response was emphatic.
"The Breeders' Cup is a possibility... I would think she will remain in training next year"
Lush Lashes galloped strongly all the way to line - but by no means had it all her own way. Nahoodh and Halfway To Heaven both tried to outflank the market leader to initiate a pulsating finish.
But Lush Lashes' class and battling spirit again came to the fore as Manning's mount claimed a neck triumph over Nahoodh, with Halfway To Heaven third.
Bolger said: "We'll discuss the options we've got for her for the rest of the season.
"There's the Sun Chariot Stakes at Newmarket, the Prix de l'Opera at Longchamp and the Hong Kong Cup that Alexander Goldrun won. The Breeders' Cup is also a possibility.
"I would think she will remain in training next year."
O'Brien, meanwhile, failed to add to his 18 Group One successes this season, when his best chance on the day, Henrythenavigator, lost out to Goldikova in the Prix du Moulin at Longchamp.
French trainer Freddie Head continued his superb form this season as his filly was given a sound ride from Olivier Peslier, gaining a clear-cut advantage two-and-a-half furlongs from home to defeat Darjina.
British raider Paco Boy was third, while dual 2,000 Guineas hero Henrythenavigator, under Johnny Murtagh, could only finish fifth.
Head said Goldikova would now "definitely go" to the Breeders' Cup.
O'Brien said: "We know that Henry loves fast ground. He has ran a good race but the top was coming off the ground.
"Johnny said he laboured a little on it and he wasn't able to get hold of it as he normally can.
"He is a fast-ground horse and speed is his big attribute, but that was blunted and he could never get into top gear."
SUNDAY'S GROUP ONE RACES
Irish Champion Stakes (Leopardstown)
1. New Approach (K Manning) 8-13 fav
2. Traffic Guard (J Egan) 50-1
3. Mores Wells (D McDonogh) 8-1
8 ran. Dist: ½ length; 1¼ lengths; Short Head
Matron Stakes (Leopardstown)
1. Lush Lashes (K Manning) 9-4 fav
2. Nahoodh (M Kinane) 6-1
3. Halfway To Heaven (J Heffernan) 4-1
10 ran. Dist: Neck; ½ length; ½ length
Prix du Moulin (Longchamp)
1. Goldikova (O Peslier) 3-1
2. Darjina (G Mosse) 8-1
3. Paco Boy (R Hughes) 7-2
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