Diamond Necklace

What makes this run even more striking is the company she has been keeping. Her final race as a two-year-old was the Prix Marcel Boussac — one of the top races in Europe for young horses — which she won with the kind of ease that suggested she had plenty more to offer. O'Brien has drawn comparisons to her sire, St Mark's Basilica, a genuinely high-class horse who improved significantly from two to three and went on to win at the highest level. The trainer notes that St Mark's Basilica did not win a top-level race until the Dewhurst — a major autumn championship — and Diamond Necklace appears to be tracking a similar path, showing real progression and natural ability without needing much help.

Looking ahead, there is talk of pitches at the French 1,000 Guineas or even the Prix de Diane, a mile-and-a-quarter race that would stretch her stamina and test whether she can handle longer distances. O'Brien has indicated that Diamond Necklace has the class and scope to excel at either trip, and her recent performances suggest she is only getting better. Coming from a yard that has already sent out 125 winners this season, she is part of a formidable operation, but her unbeaten record and the calibre of her opposition mark her out as something special — a horse that might just be at the very beginning of a significant career.