Thundering On faces Pretty Polly Stakes test on Curragh return

Thundering On goes to the Curragh on Saturday with the kind of profile that forces a race to tell the truth. Joseph O’Brien’s Oaks winner will face the Pretty Polly Stakes over 1 mile and 2 furlongs, a Paddy Power-sponsored Group 1 worth €300,000, and the question is whether Epsom was a peak or the beginning of a bigger run.

Her route into the race has been almost flawlessly upward. Thundering On was beaten a short head on her seasonal debut, then landed the Salsabil Stakes at Navan by 3¼ lengths before blowing away the Epsom Oaks field on June 5, a result that gave Joseph O’Brien his breakthrough Classic victory as a trainer. After Epsom, O’Brien called the filly “very impressive,” said “This is really special,” and added that she had “done nothing wrong throughout her whole career.” He also said she “could potentially be a special filly,” and Saturday’s race is the first chance to see whether that assessment still holds against older, more battle-hardened opposition.

What has to translate from Epsom is not just class, but control. Thundering On has already shown that she stays the trip and can finish her race with authority; the Curragh test is whether she can do it again against a better-drawn, deeper field and under a more searching tactical setup. The Pretty Polly often rewards a filly who can settle, move when the race starts in earnest and keep finding through the final furlong, and that matters here because the line-up is strong enough to punish any sign of overreach.

Estrange looks the obvious danger after winning the Betway Lester Piggott Fillies’ Stakes at Carlisle by 1½ lengths on May 30, her only start of the year. One Look brings course-and-distance winning form and an added Royal Ascot boost, while Red Letter arrives after finishing runner-up to See The Fire in the Middleton Stakes and takes a third crack at Group 1 level. Aidan O’Brien’s sole representative is Beautify, Charlie Johnston sends Venetian Lace and Ed Walker has both Carolina Jetstream and Qilin Queen in the field, while Joseph O’Brien also has Nyra and the outsider Wemightakedlongway among the entries.

The race has a habit of measuring where a top filly fits in the summer pecking order. The Curragh says 13 of the 25 Pretty Polly renewals this century have gone to British-based trainers, with Joseph O’Brien winning it with Iridessa in 2019 and Thundering Nights in 2021, and Aidan O’Brien last taking it with Magical in 2020. Thundering On can turn the race into a straight line toward deeper late-summer and autumn targets if she repeats Epsom; if she does not, the market around Europe’s leading staying fillies gets a lot more open.