Sea Of Class was among the stars of last year (FocusOnracing)
Last year’s Irish Oaks winner underwent surgery after being struck down with the life-threatening illness two weeks ago, but despite the best possible care, her condition deteriorated on Monday morning.
“She was a marvellous filly and obviously she had a huge amount of ability,” said the Newmarket trainer.
“She was very intelligent and very clever. She fought very hard, but today has been a sad day.”
Sea Of Class won four races in a row in 2018, culminating in the Yorkshire Oaks, and then got within a short neck of catching Enable in a pulsating renewal of the Prix de l’Arc de Triomphe at ParisLongchamp in October.
Watch how Sea Of Class shone in the Yorkshire Oaks
The line came just in time for Enable, who became only the eighth horse in history to win the Arc twice.
Sea Of Class, who had to weave her way through from a wide draw after typically racing in rear, finished with a rattle under James Doyle and was eating into her advantage with every stride near the finish.
She ran just the once this year, when fifth in the Prince of Wales’s Stakes at Royal Ascot on unsuitably soft ground.