The three-year-old showed immaturity first time out but his talent shone through as he cruised to a comfortable two and three-quarter length win.
"He's a young horse and even you can tell he's just a baby, he still has to learn," So said at Sha Tin this morning, Friday, 5 July.
"He still needs to learn and in his trial he seemed alright, but when he's put under pressure he doesn't know yet. For now, he won't go for 1200 metres, the straight is easier for him, he has a lot of speed and he doesn't need to worry about figuring out the turn."
Classic Unicorn arrival as an unraced New Zealand import with two barrier trials under his belt and So has been impressed since day one.
"That's why after the first trial here, I gave it to the champ (Zac Purton) to try," So revealed. "We knew the horse even when he trialled in New Zealand, he won by 12 lengths, we saw the replay of the trial - we know he has a lot of speed."
Classic Unicorn was put through his paces in a trial on the dirt late last month, finishing off in an untested manner under Jack Wong. Derek Leung takes the race day reins from Zac Purton on Sunday, with the champion jockey - unable to ride at Classic Unicorn's allotted 116lb - set to partner Seven Heavens (133lb).
"I galloped him in the morning and he gave me a great feel," Leung said. "He has a very good action and last time he won impressively in Class 4. Now, up to Class 3 with a light weight, the race looks good for him."
Leung expects the pace to be a testing one for the inexperienced Per Incanto gelding.
"I can see quite a few horses will go forward, so it will be challenging for him early, for the new horses it is quite difficult when the horses next to him all challenge him," the jockey said.
So is wary of his former boss Caspar Fownes's galloper Seven Heavens who drops back to Class 3 in search of his first Hong Kong win at start 17.
"It's tough, Caspar's horse is also strong, mine is only three years old and he still needs the chance to develop," So said.
Purton, who steered Classic Unicorn to his debut victory, will reunite with Seven Heavens but spoke highly of So's galloper.
"Classic Unicorn's got a lot of speed, he's going to be forward, he's got a light weight and he's coming off a nice win, so he's definitely the one to beat," he said.
"He went well (first up), he's still very raw, he did a little bit wrong but he was still too good and he's always shown in all his trials that there is something there. He'd take a bit of a confidence out of that and he should be hard to beat again," he added.
Purton's mount Seven Heavens was luckless in defeat over this course and distance three starts ago when blocked for a run over the closing stages, and, following the demotion of the winner, he was promoted to third.
"I mentioned to Caspar a long time ago that I thought the straight was probably going to be a nice track and distance for him and he's probably run his best race at this track and distance," Purton said.
"He gets the drop in grade – the tempo of this distance suits him and he doesn't have to think too much because he's going in a straight line."
Moore needs Magic
Purton secured a double on Wednesday (3 July) night and will look to help John Moore close the two-win gap on John Size in the race for the trainers' premiership, when he rides Magic Success (131lb) in the Class 4 Beas River Country Club Handicap (1400m).
"It's all just tempo related for him, if he can sustain a nice rhythm on a nice speed I think that's his key, if it's stop-start I don't think that suits him," Purton said.
Magic Success was found to have had blood in the trachea after his last start and will be without the blinkers he wore that day as he steps up to 1400m for the first time under Moore's care.
"It depends on the tempo of the race probably more so but the blinkers coming off might help him to relax as well," he continued.
Purton is as excited as anyone that the trainers' premiership is continuing to heat up with Moore on 72 wins and Size on 74 with four meetings to go.
"I think it's good, I always say that competition is good, it's what keeps people interested, so there's obviously a lot of talk about it and let's just hope it goes down to the last day," he said.
Sunday's 11-race card begins at 12.30pm with the Racing Club Plate (1200m) for Griffins.