Irish trainer Aidan O’Brien, the only handler with runners in all four of Sunday’s Group One events at the Longines Hong Kong International Races, arrived in the city on Wednesday morning and headed straight to Sha Tin to oversee their trackwork sessions.

Aesop’s Fables, Cairo, Luxembourg and Warm Heart will represent O’Brien in this weekend’s features. While the three-time Hong Kong Vase-winning conditioner is generally reluctant to rank his gallopers publicly, his trackside comments suggest the longer the race, the better chance he thinks he has of success on Sunday.

O’Brien, whose stayers Highland Reel (2015 and 2017) and Mogul (2020) have won three of the past eight editions of the Hong Kong Vase (2,400m), will run Warm Heart in this year’s HK$24 million contest.

Warm Heart, the Galileo three-year-old filly out of three-time Group One-winning sprinter Sea Siren, has two elite-level victories over extended trips on her resume and travelled to Hong Kong following her neck second to Inspiral in last month’s Breeders’ Cup Filly & Mare Turf (2,000m) at Santa Anita.

“It was the plan [to bring Warm Heart to Hong Kong]. She’s a very consistent filly, she has a nice weight pull, and she’s well in,” O’Brien said, confirming Ryan Moore would ride his lightly weighted runner.

“We were a little bit unsure about whether to go to the mile and a quarter [Cup] or the mile and a half [Vase]. She looks like she might be a little bit better at a mile and a half even though she comes out of a great race over a mile and a quarter.”

Luxembourg, a Group One champion at two, three and four, will line up for O’Brien in the Hong Kong Cup (2,000m) against the likes of local hero Romantic Warrior and Japanese return visitor Prognosis.

“He’s a very good horse,” O’Brien said of his four-year-old galloper with three top-level triumphs in tandem with Moore. “He was second in the Irish Champion [Stakes at Leopardstown], and he was going to go to the English Champion [Stakes at Ascot]. He got a foot bruise, and that put him out of that, [but] this was the race we always had our eye on.

“He’ll be leading over a mile and a quarter, I’d imagine, and hopefully, he runs well. It’ll be a nice race to watch. He’s a very good horse, Romantic Warrior. We totally respect every horse, really.”

Whereas Warm Heart and Luxembourg have won Group Ones, Cairo and Aesop’s Fables are still looking to break through in the highest grade. According to O’Brien, his Hong Kong Mile and Hong Kong Sprint (1,200m) representatives remain works in progress for whom this year’s contests may come too soon.

“He was second to Paddington, and then he had a long break,” O’Brien said of Cairo. “We were looking for a run to get him back, and he ran at Leopardstown in a Listed race on very soft ground. We thought he’d have to improve a lot from there. We think he has.

“We think the experience will do him good. He’s going to be a horse for next year as well. We’ll be delighted if he runs a nice race and comes forward. He has some very good form at his best, and we think he’s a horse we’ll see plenty of from here on in.

“Ryan says it’s going to be tough for a three-year-old sprinter, but he has progressed a lot in his past two runs,” O’Brien said of Aesop’s Fables.

“[We] put blinkers on him for the Abbaye, and it really stepped him up. He’s back to six [furlongs] after two runs over five [furlongs]. He’s a big, powerful horse. He will improve from three to four, [and] we think the experience will do him good.”