The Frankie Lor-trained three-year-old showed good speed and shrugged off the attentions of useful top-weight Fabulous Eight to win with plenty in hand in a smart 55.59s for the 1000m journey.
Purchased for $300,000 by Tartan Meadow Bloodstock's Paul Chow from the Haunui Farm Book 1 draft in 2018, Winning Dreamer won two trials in New Zealand for Alex Oliveira before making his way to Lor's operation in Hong Kong.
Bounced straight to the lead by rider Vincent Ho, Winning Dreamer eased clear over the final 200m to register a performance that delighted his connections.
"He has a bright future and hopefully he'll be in Group races in time," Ho said of the $2.40 favourite.
"He jumped well and relaxed really nicely in the race and just kept going.
"He's still got a lot to learn but it's been better each time he's had a barrier trial – he was very green and he settled more on the turn in his last trial."
Lor was pleased with his debutant who may be seen in action again before the close of the Hong Kong racing season on July 15.
"He's got quality but he's still green and was laying in through the final stages, so I'd like to give him one more run before the end of the season," Lor said.
Bred by Matt Goodson and Di Perron, Winning Dreamer is the fourth winner from Group Three placed mare Markisa, who is also the grand-dam of Group winners The Real Beel and Catch Me.
A member of the illustrious Eight Carat family, Markisa is a half-sister to Group One winner Shower of Roses and daughter of Group One winner Marquise.New Zealand-bred runners also featured prominently during the day with Mastercraftsman five-year-old Racing Fighter returning to form with a win over 1200m while Darci Brahma gelding Mr Croissant, a half brother to Gr.1 New Zealand Stakes (2000m) winner Sakhee's Soldier, lodged his third win of the season when successful in a Class 2 1200m contest.