Kew Gardens gave Aidan O'Brien a sixth success in the William Hill St Leger at Doncaster in holding off the late challenge of favourite Lah Ti Dar.
Ryan Moore's mount won well at Royal Ascot in the summer, before adding the Grand Prix de Paris to his CV, and ran a good Leger trial when third in the Great Voltigeur Stakes at York.
Frankie Dettori had tracked Moore aboard Lah Ti Dar, but the market leader's inexperience seemed to tell half a mile out and it was to her credit she ran on so well at the end.
Two and a quarter lengths was the margin of victory for Kew Gardens (3-1), with his stablemate Southern France another four and a half lengths away in third.
Moore told ITV Racing: "It was very smooth. He's a very uncomplicated horse and he tries very hard. He's got a great attitude to life and he picked up really well. He's a super horse."