Grosvenor Square a serious player for St Leger as Aidan O'Brien continues to dominate Classics betting into next year

Grosvenor Square didn't look anything special on his first two runs of the season but the picture has changed markedly since his distant third in the Chester Vase was followed by a distant seventh (of eight) in the Irish Derby.

The Aidan O'Brien-trained colt is now as short as 8-1 for the St Leger after a 20-length romp at the Curragh on Saturday. That effort backed up his previous good run in the Curragh Cup, in which he just got collared by stablemate Tower Of London close home with seven lengths back to Vauban in third.

He has to be a serious player at Doncaster in a race that looks highly likely to go back to Ballydoyle, with Jan Brueghel, Los Angeles, Illinois and Highbury all legitimate contenders.