Ranking Aidan O'Brien's Royal Ascot contenders

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June 12th, 2021

Aidan O’Brien has been a dominant force at Royal Ascot in recent years. The acclaimed Irish conditioner has ranked as the leading trainer at the prestigious five-day meet on 10 occasions, including five in a row from 2015-2019.

All told, O’Brien has won 74 races at Royal Ascot, easily the second-highest total behind Sir Michael Stoute (81). O’Brien figures to add to his win tally in 2021, when he’ll saddle a deep roster of juveniles, sophomores, and older horses in a variety of races across the June 15-19 meet.

Kevin Blake of attheraces.com recently gathered O’Brien’s thoughts on a bevy of runners targeting Royal Ascot. In preparation for handicapping the races, we’ve gone through the notes and quotes and divided 10 of O’Brien’s horses into three categories, based on their apparent chances for victory:

Group A: Primary win contenders


A four-time group stakes winner, Armory kicked off 2021 with a decisive three-length victory over good-to-soft ground in the Huxley S. (G2) at Chester. The effort surprised O’Brien, who expects the four-year-old son of Galileo to produce an even stronger performance in the Princes of Wales’s S. (G1).

“The plan after Chester was always to go on to the Prince of Wales’s S. and that is still the way we are thinking,” said O’Brien. “We were worried that the ground might be a bit soft for him at Chester, so for him to be so impressive there was very encouraging. He’ll be much better suited by firmer ground. We’ve been very happy with him since Chester and he seems like an improved horse this year.”

Mother Earth

Runner-up in the 2020 Breeders’ Cup Juvenile Fillies Turf (G1) at Keeneland, Mother Earth has been in strong form this season, winning the 1000 Guineas S. (G1) at Newmarket before finishing second in the Poule d’Essai Pouliches (French 1000 Guineas) (G1) over very soft ground at ParisLongchamp. She’s aiming for the Coronation S. (G1), and O’Brien is expecting another good effort.

“She ran very well in the French 1000 Guineas in a race that didn’t go ideally for her. She has seemed to be in good form since and the plan is to run in the Coronation S.,” said O’Brien. “She is versatile with regard to ground and I think Ascot will suit her.”

Order of Australia

Although Order of Australia has won over 1 1/2 miles and competed in the Irish Derby (G1) last season, the son of Australia has proven best over one mile, securing his biggest victory in the Breeders’ Cup Mile (G1) at Keeneland last fall. Although he’s yet to race in 2021, Order of Australia has been specifically pointed toward the Queen Anne S. (G1) on opening day at Royal Ascot and should produce a strong effort.

“We are training him as miler this year and have had it in mind to start him off in the Queen Anne S. all season,” said O’Brien. “The track should suit him well and he seems to be in great order. We are looking forward to seeing what he can when focusing on a mile for a full season.”

The Acropolis

One of O’Brien’s best juveniles appears to be The Acropolis, who finished fourth in his debut at the Curragh before improving to trounce a June 6 maiden race over yielding ground at Listowel. The Coventry S. (G2) is his Royal Ascot target.

“He’s a horse we’ve always liked a lot,” said O’Brien. “We thought he’d be tough to beat at the Curragh on debut, but it didn’t work out for him on the day. We wanted to give him another run before Royal Ascot and were tight on time which is why he ran at Listowel. He won in good style there and will appreciate the firmer ground he’ll get at Ascot. He works with a lot of class.”

Group B: Logical, but not unbeatable runners

Empress Josephine

Winner of the Irish 1000 Guineas (G1) over soft ground at the Curragh, Empress Josephine has her eye on Royal Ascot’s Coronation S. (G1). But O’Brien admits the transition to firmer ground is a question mark for the three-year-old daughter of Galileo.

“There is a fair chance she’ll be supplemented into the Coronation,” said O’Brien. “She handled soft ground in the Irish 1000 Guineas and the ground will be very different at Royal Ascot, but at the moment we think we’ll let her take her chance. She did it well at the Curragh and has seemed in good form since then.”


One of the most high-profile runners O’Brien will saddle at Royal Ascot is Love, a spectacular winner of the 2020 Epsom Oaks (G1). The daughter of Galileo will be a short price in the Prince of Wales’s, but she hasn’t run since August, and O’Brien is taking a big-picture view in preparing Love for her seasonal debut.

“She’s in great form. She’s been waiting a long time to start back, but we just didn’t want to start her on soft ground, as we are hoping to have a long season with her and that just wouldn’t be the right way to start her off,” explained O’Brien. “The ground just didn’t come right for her to this point… She’s never run over a mile and a quarter, but everything about her would suggest that it should suit her well. We are very excited to see her back on the track.”


It’s likely Prettiest will take a step forward in the Albany S. (G3), since O’Brien notes she wasn’t fully cranked for her debut victory at Navan. But the daughter of Dubawi has been geared up earlier than planned to pursue Royal Ascot, suggesting we might not see her best until later in the year.

“We had Contarelli Chapel in mind for the Albany Stakes, but she chipped a knee in her last start and isn’t going to make it to Royal Ascot,” said O’Brien. “(Prettiest) was coming along lovely and always showed plenty, so we said we’d start her off a bit earlier than we’d originally planned just to see if she could slot into that gap in the Albany. We expected her to need the run quite badly, but she was very professional and won nicely at Navan. She was getting a little bit tired close home, but she was entitled to as she hadn’t had a big prep for it. She’s a very natural filly and when you ask her for more, she really puts her head down and tries.”


Winner of the 2020 Irish Derby, Santiago has already tasted success at Royal Ascot, nabbing the Queen’s Vase S. (G2) last season. The question now is whether the bay four-year-old can replicate his best form over an unfamiliar 2 1/2-mile journey in the Gold Cup (G1).

“He’s in good form,” said O’Brien. “The trip is an unknown for him, but we’ve trained him to peak for Royal Ascot and hopefully he’ll be able to prove his stamina for this longer trip.”

Group C: Runners who may prove better down the road


Dundalk maiden winner Cadamosto will switch from synthetic to turf for the Norfolk S. (G2), but O’Brien cautions the son of No Nay Never isn’t cranked for a peak performance.

“He won impressively at Dundalk. We really wanted to get at least a second run into him, but we didn’t want to run him on soft ground and it just didn’t happen for him,” explained O’Brien. “He’s very fast and wants quick ground. It’s far from ideal not getting another run into him, as he’s been waiting a long time since his debut. For that reason, it wouldn’t be a big surprise if he took a fair step forward from whatever he does at Royal Ascot.”


A Dundalk debut winner aiming for the Queen Mary S. (G2), Yet might not be ready for a peak effort at Royal Ascot, with success during the summer and fall a more likely possibility.

“She’s a big filly and I think she’ll progress with racing,” said O’Brien. “She’s a sleepy, lazy filly at home that isn’t flashy in her work, but she looked a lot sharper when she ran at Dundalk.”