Romantic Warrior’s history-making Group One Cox Plate (2,040m) victory will surely prove to be his most exhilarating and unforgettable 2023 achievement.

However, the four-time Group One winner’s final act of the year might be his most important.

Romantic Warrior overcame all sorts of adversity – feed issues, stringent veterinary procedures, unfamiliar surroundings – to plunder Australia’s most prestigious race.

His efforts were the talk of the town, and Peter Lau Pak-fai’s sense of adventure was an inspiration to fellow owners.

A below-par showing in his Group One Hong Kong Cup (2,000m) defence on Sunday, though, would set tongues wagging at an even greater rate.

At a time when risk-averse owners are not willing to look past the potential pitfalls of travel, a Romantic Warrior flop this weekend would add considerable weight to their approach.

Should Romantic Warrior turn up at his best – or close to it – and show he has come back from his travels in tip-top shape, the upside in regards to Hong Kong’s presence abroad could be significant.

However, the pass mark cannot be to win, for whatever Danny Shum Chap-shing’s superstar has been through already, his toughest task on the track looks yet to come.

In Japanese pair Prognosis and Rousham Park, Aidan O’Brien’s Luxembourg and French three-year-old Horizon Dore, Romantic Warrior faces serious opposition.

A touch ironic is the fact master Irishman O’Brien is the only trainer this century, and perhaps ever, to take a horse – 2015 Group One Hong Kong Vase (2,400m) victor Highland Reel – from a Cox Plate run to a Hong Kong International Races (HKIR) victory on their next start.

O’Brien means business – “no doubt” was his answer when asked if his four-pronged attack is the strongest he has ever launched on HKIR – and Luxembourg is the highest-rated horse he has brought to Hong Kong since Highland Reel.

Prognosis is hungry for redemption, and while it was Zac Purton in the saddle when the five-year-old finished second to Romantic Warrior in April’s Group One QE II Cup (2,000m), star Japanese jockey Yuga Kawada will be on his back this weekend.

Whether that will make a difference for a galloper who was slow away before finishing two lengths adrift in April remains to be seen, but overseas fixed-odds bookmakers have him installed as the clear second favourite at $3.80.

There has been plenty of chat this week that Romantic Warrior is more than worth risking at $2.70 considering the enormity of the assignment and his taxing trip Down Under, but the stable is exuding a quiet confidence that suggests they are expecting something big on Sunday.

Jockey James McDonald, who is making a flying – and somewhat risky – trip to Perth to ride Zaaki in Saturday’s Group One Northerly Stakes (1,800m), has marvelled at Romantic Warrior’s ability to improve markedly in a short space of time, and the galloper’s physio, Tom Simpson, revealed on Thursday that “he’s really sparked up this week”.

No horse has won a Hong Kong Cup by more than Romantic Warrior’s four-and-a-half-length margin 12 months ago. This weekend, as he looks to join California Memory as a two-time winner of the city’s richest race, a whisker will do.