Brilliant filly Snowfall suffers fatal injury

The daughter of Deep Impact would surely have had a further great career ahead as a broodmare, but that is not to be.

After winning just once, at the Curragh as a two-year-old, she reappeared with a shock 14-1 win in last year's Group 3 Musidora Stakes at York. She did that impressively from Noon Star and a step up to Group 1 level was her reward.

Partnered by Frankie Dettori in the Oaks, after Ryan Moore had preferred Santa Barbara, she sluiced up a yawning 16 lengths at 11-2.

Proving that no fluke, she went on to win the Irish equivalent by eight and a half lengths and then added the Yorkshire Oaks.

That was her last win as she was beaten by Teona in the Prix Vermeille, finished sixth in the Arc and third on Champions Day at Ascot.

No decision had been taken on whether the four-year-old would remain in training this year or head off to stud.

"It's very sad news, terrible," said O'Brien.

"The lads were thinking of keeping her in training but they hadn't quite made up their minds, it was very possible.

"She had a pelvic injury in her box. Sometimes pelvic injuries go the right way or they can go the wrong way, unfortunately this one went the wrong way.

"It's very sad and I feel very sorry for the lads, for Derrick (Smith), Michael (Tabor) and John (Magnier)."