A fitting finale for the three-time Group 1 winner to bow out in, Waikuku's career will embrace one more confrontation with Golden Sixty – whose 16-win streak he famously halted in the 2022 G1 Stewards' Cup (1600m) under Zac Purton.
"I'm pretty sure this will be his last run. We will retire him after Sunday, so hopefully all goes well for him and then he can enjoy his retirement," Size said.
The eight-time winner and earner of HK$47.06 million in Hong Kong, Waikuku also boasts wins over former champion Beauty Generation in the 2019 G2 Jockey Club Mile (1600m) and 2020 Stewards' Cup for Size, who will remember the Harbour Watch gelding's heroics fondly.
"He's been wonderful, he won three Group 1 races and he ran second in the Hong Kong Derby. It was one of those races that could have been more interesting for him, but he still acquitted himself very well and he always does," Size said.
While the hallmark of the eight-year-old's career became his giant-slaying ability, in 2019 he almost landed a BMW Hong Kong Derby (2000m) crown. The mastery of Size saw Waikuku overcome a sore foot in the lead-up to the race, only to finish a brave second behind Furore.
"He'll give whatever he's got, he'll run his best and he'll get a nice run in the race – he'll be fourth or fifth one off the fence and the acceleration of the good ones will be superior, but hopefully he gets around safely and enjoys the rest of his life," Size said.
Along with a pair of Stewards' Cup wins in 2020 and 2022, Waikuku's other top-level triumph came in the 2021 G1 Queen's Silver Jubilee Cup (1400m).
Waikuku is part of a three-pronged assault for Size on Sunday's HK$65 million FWD Champions Day feature races with Sight Success and Courier Wonder representing the 11-time Hong Kong Champion Trainer in the HK$20 million G1 Chairman's Sprint Prize (1200m).
Sight Success has placed twice at Group 1 level this season in Hong Kong.
"He's got some speed; he'll go forward from there and Master Eight will probably go with him or in front of him. These races on the weekend, they're all small fields and there's always some tactics involved but the gate's not as important compared to when you have 14 runners," Size said.
Sight Success has continued to improve this season, finishing second in the 2022 G1 LONGINES Hong Kong Sprint (1200m) before winning January's G3 Bauhinia Sprint Trophy Handicap (1000m).
"He helps himself a lot and the jockeys are always very complimentary about his performances and his attitude. He always gives whatever he has in the tank, he'll give it for the riders and his consistency has been very good. Hopefully one day that pays off for him with a lucky win somewhere," Size said.
Sight Success will be ridden by James McDonald first-up following the horse's courageous fourth in March's G1 Al Quoz Sprint (1200m) at Meydan in Dubai, while Courier Wonder pairs with Hugh Bowman.
"He's (Courier Wonder) been running well and he didn't have much luck in the run last start. It was a bit of an awkward race for him and he wasn't able to perform but his previous couple of starts were very encouraging and hopefully he can run into some prize money as well," Size said.
Courier Wonder had a setback last year but did show tremendous ability early doors, winning his first five races before placing at Group 1 level.
"He has plenty of pace but he doesn't manage himself correctly now that he's come up in class. His first five starts were too easy for him. He didn't actually learn how to race properly and then when he went into proper competition against his equals, he had to develop a racing style which didn't come naturally to him.
"He had to be trained and governed that way, to teach him how to use his energy properly and to his credit he appeared in the (2022) Hong Kong Sprint to run a very good fourth as a 100/1 chance and that was his true form that we were hoping he'd get to," Size said.
Courier Wonder and Sight Success will step away from gates four and one, respectively.
"He's shown his true ability but similar to Sight Success, he needs a bit of luck to grab the major end of the prize," Size said.
Sunday's (30 April) 10-race FWD Champions Day fixture kicks off at 12.45pm with the Class 4 FWD Insurance Goahead Group Handicap (2000m).
