Tourbillon Diamond had to endure questions over his zip before turning heads with an impressive mile victory at his second Hong Kong start and Danny Shum Chap-shing hopes for a repeat dose at Sha Tin on Sunday.

After a closing seventh in last month’s Hong Kong Derby (2,000m), Tourbillon Diamond has had a brief freshen-up and returns in one of the two Class Twos on the Champions Day undercard – the FWD Insurance Act Champion Handicap (1,600m).

While he won at 1,300m and a mile while racing as Eric The Eel in Australia, Tourbillon Diamond’s final and perhaps best showing pre-import was his third in the Group One Australian Derby (2,400m), leaving many thinking he was an out-and-out stayer.

His maiden Hong Kong outing, when he rattled home for third over seven furlongs, indicated this may not be the case and Shum admits he’s still working out the four-year-old’s best trip.

No longer Eric The Eel, Classic Mile contender Tourbillon Diamond finds his speed

“It’s hard to tell what his best distance is but he won at the mile so he deserves another chance at the mile. He trialled well [last week] and he’s happy, so I think he will run well,” Shum said.

Zac Purton takes the ride for the first time after Vincent Ho Chak-yiu was in the saddle for the Derby and Tourbillon Diamond’s win, with Shum pleased to acquire the services of the jockey who has ridden exactly half of his 50 winners so far this season.

Tourbillon Diamond is one of four horses in the race who competed in this year’s four-year-old series, along with Maximus, Arthur’s Kingdom and Celestial Power, and one of a host of up-and-coming types on Sunday’s card who could have an impact at Group One level in the future.

The Class Two FWD Insurance My Legend Handicap (1,200m) is headlined by explosive John Size-trained three-year-old Courier Wonder, who looks to be on a fast-track to the top level after climbing 36 points in the ratings across three impressive victories.

Frankie Lor Fu-chuen’s four-year-old Winning Dreamer is also in the race and returns to Class Two level for the first time since ringing up his sixth consecutive victory on international day in December, while Lucky Patch has his second start back at six furlongs after finishing 12th in February’s Classic Cup at 1,800m.

Earlier in the day, Size saddles up another undefeated three-year-old in the Class Three FWD Insurance ICBC (Asia) Handicap (1,200m), with Fantastic Way looking to make it four on the trot.

Harry Bentley lands his maiden Hong Kong winner with his first ride at Happy Valley

The gelding will have to do it the hard way under the top weight of 133 pounds from barrier nine against a field that includes another sharp three-year-old in David Hayes’ Trader, who jumps straight into Class Three after a length-and-three-quarter victory on debut.

Other precocious youngsters on the undercard include Size-trained pair Gallant Express and Beauty Fit, who searches for his first Hong Kong win at start three after racing as Barocha in Australia, and another Hayes galloper in Packing Award, who has the services of Purton as he looks to go one better than his runner-up showing on debut.