JOSEPH O’Brien bids to bring a career-best season to new heights at ParisLongchamp on Sunday, where his three Group 1 contenders hold leading chances, including Epsom Oaks heroine Thundering On in the feature race of the day, the Qatar Prix de l’Arc de Triomphe.

The prestigious prize was to the fore of O’Brien’s mind following Thundering On’s most recent win in a strong renewal of the Blandford Stakes, which marked a return to form after a mildly disappointing fourth against her elders in the Pretty Polly Stakes.

On the decision to run the three-year-old filly against colts in France, rather than keep her with own sex in the Prix de l’Opera, he told The Irish Field: “These decisions are always made in discussions with the ownership and we all felt that this was a good distance for her and there’s only one Prix de l’Arc. We felt with what she has done so far this season, she’s earned a crack at the race.”

On whether the Prix de l’Arc de Triomphe is top of O’Brien’s wishlist, he replied: “I dunno about that, but there’s not many bigger ones anyway. It’s special to be going to the race with a live competitor and we’re excited about the prospect.”

Thundering On bids to become the 14th three-year-old filly to win the race, joining such illustrious winners as Treve, Enable and Zarkava, and has a low draw in stall three to enhance her chances. Five of the last 10 winners were drawn four or lower, with just two breaking from a double-digit stall.

Last year’s victor Daryz has been handed stall five, with leading market rival Kalpana in six, her price shortening compared to William Haggas’ Grand Prix de Paris winner Maltese Cross in 11. Diamond Necklace’s wide draw in 16 has seen Ryan Moore jump ship to Benvenuto Cellini on the inside rail.

Dylan’s deputies

With Dylan Browne McMonagle still ruled out due to injury, Thundering On will be ridden by Pierre-Charles Boudot for the first time on Sunday, while Mickael Barzalona is booked to ride Folsom Blues in the Prix Jean-Luc Lagardere and Christophe Soumillon gets the leg up on Prix Marcel Boussac favourite Green Empress.

On whether jockey bookings proved the greatest challenge in the lead-up to the meeting, O’Brien commented: “Obviously, we’d love to have Dylan for the weekend, but we’re lucky enough that we’ve been able to get some of the top guys in France for all three runners, so we’re happy with how that has worked out.”

The ground has been another major influence on the betting, with continued dry weather likely to result in good ground at what has traditionally been a fruitful fixture for horses who enjoy a cut in the ground.

Thundering On’s classic success came on good-to-soft ground, but her latest win on good ground suggested she is at least somewhat versatile.

Stablemate Folsom Blues has run well on various ground, but his two wins have come on soft (when winning his maiden by seven and a half lengths) and yielding (when bolting up in the National Stakes last time out).

However, O’Brien isn’t concerned about the likelihood of good ground for this weekend and expects it to particularly suit his first runner of the day, Green Empress, who will also appreciate the absence of her regular rival, Sun Goddess.

“She will probably love this better ground,” he said of the Debutante Stakes winner and Moyglare Stud Stakes runner-up.

“As you say, it’s nice not to have Sun Goddess - she’s been second to her three times now.

“We’re looking forward to going a bit longer with her; she’s out of a Sea The Stars mare.”