Donnacha Aidan O'Brien

This season, O'Brien has sent out 31 winners from 226 runners, which works out at roughly 1 in every 7 races — a 14% win rate that holds up well for a yard still finding its feet at the top table. What makes those numbers more impressive is the quality sitting behind them. He has won four top-level races in his career, with victories at Ascot and Newmarket among them — including a Class 1 success at Ascot in June 2024 and another at Newmarket the previous September. These are not races you stumble into. They are the hardest races in Britain to win, and O'Brien has managed it more than once.

He seems particularly at home when the rain arrives. On wet or muddy ground, his runners win roughly 1 in every 4 or 5 races — 5 wins from 23 runners, a 22% win rate that climbs well clear of his overall average. Whether that reflects a deliberate preference in how his horses are trained or simply a sharp eye for when to run them, it is a pattern worth paying attention to. Similarly, Killarney has been a happy hunting ground: 4 winners from just 13 runners there is a return that any trainer would be pleased with.

His most trusted partnership in the saddle is with jockey Gavin Ryan, who has ridden 16 winners for the yard from 117 races together — again that same 14% win rate, suggesting a consistent and well-drilled operation rather than one relying on luck or timing. His most notable single partnership, though, is with Emmeleia, who has won 1 of their 3 races together — a record modest in volume but not in significance given the level at which that win came.

One hundred winners in four years, four victories in the sport's biggest races, and a clear feel for when and where to place his horses to best effect. O'Brien the trainer is shaping up to be every bit as formidable as O'Brien the jockey once was.