Group 1 horses are forged in the heat of battle - and the O'Briens understand that much better than anyone else

Apart from the bleeding obvious, what do Aidan, Joseph and Donnacha O'Brien have in common? Or to put it another way, what is the common denominator that has helped all three of them repeatedly make their mark in Pattern races this year?

Between them they have dominated the Group 1 action in Britain and Ireland this month, starting with Aidan's Constitution River beating Donnacha's A Boy Named Susie in the Coral-Eclipse at Sandown on the first Saturday in July.

The following weekend Donnacha took his revenge when Comanche Brave landed the July Cup at Newmarket, and on the Saturday just gone, Donnacha's older brother Joseph beat four runners trained by their dad when Johanna Walsh strolled away with the Irish Oaks at the Curragh.