Kew Gardens (3/1) showed all his class to give trainer Aidan O’Brien his sixth win in the William Hill St Leger.
O’Brien’s colt came into the race already a Group 1 winner having won the Grand Prix de Paris before his third in the Great Voltigeur.
Punters were keen to back John Gosden’s unexposed filly Lah Ti Dar (7/4f) and she went off the favourite but could only manage second behind Kew Gardens as Ryan Moore steered him to an impressive win in the Classic.
O’Brien also saw his Southern France (20/1) come home third.
The Ballydoyle handler said: "We couldn't be happier with him, he's a horse that has progressed lovely and we saw what he could do at Ascot and we were over the moon with him there.
"We always thought he was a horse that would stay well. We were delighted with him in France and he has a lot of class as he showed today.”
Gosden was thrilled with Lah Ti Dar’s run and revealed that the star filly is set to stay in training next year.
He said: “We've been beaten by a Group 1 winner, she's run an absolute blinder and we're thrilled with her.
“We will freshen her up and go to the Fillies' and Mares race at Ascot on Champions Day.
"We're absolutely thrilled with her. We'll run her at Ascot and put her away for next year."
It was not to be a dream double for the team of Dettori, Gosden and owner Lord Lloyd-Webber, but they have an exciting colt on their hands in the form of Howcroft Industrial Supplies Champagne Stakes winner Too Darn Hot (4/11f).
The colt came into the race with a lofty reputation and he left with an even higher one following his stylish victory.
Dettori was equally impressed and said: “I had a look about halfway and saw where the leaders were and thought forget about it, I'm going to go after the others.
“What he did was amazing. He made six lengths in two furlongs. He is very special.
"He was great, today is the first day I've ridden him on a Flat track and he gave me a really good feel. He went through the gears so well.”
It was a special victory for Andrew Lloyd-Webber and his wife Madeline after he revealed the colt had had to overcome a number of setbacks.
Lloyd-Webber said: “This is a very unusual one as Madeline never ever keeps the colts. This one had a minor injury and we thought that we couldn't sell him.
"For him to be a homebred, to be the first colt and for him to have come through an injury when he was very small, I think it's very special for her.
"It's quite an exciting thing really, we didn't think the horse would ever race.
“Then he got better, he was broken in and then he got better there and I think I saw him when he was broken and thought he looked really terrific - not that I know anything!
“And then we went from there really."
Phoenix Of Spain (8/1) lost little in defeat as he chased the impressive winner home with Cardini (40/1) staying on for third.
William Hill cut Too Darn Hot into 7/2 for the 2,000 Guineas next year and 4/1 for The Derby as the colt now heads the betting for the two Classics next season.
