The raging favourite for the James Squire Handicap (1100m), where he was $1.55 with TAB on Thursday, scored by 7-1/2 lengths in his sole public hitout back just under two weeks ago.
And while margins can be misleading in trials, Sterling Alexiou said that particular trial was important as both a fitness and educational tool for the colt.
"We always knew he was going to have the one barrier trial going into his first race start,'' Alexiou said.
"So we wanted him to have a bit of a hitout and get him off the bit, educate him a bit.
"He jumped well, put himself on speed, rested, and when Tim asked him for an effort he skipped clear and eased down a bit.
"It's always hard to win Saturday races off one trial but hopefully he's one that can do it."
Amazing Eagle, a $400,000 purchase, puts his Magic Millions credentials on show and there'll be no better man on board than Tim Clark to tell connections where he stands.
Clark partnered current Millions favourite Storm Boy to his debut win two weeks ago and he's had the benefit of partnering the Capitalist colt in his trial.
Alexiou said it's long been the plan to wait until now to begin his career and target the sales restricted feature.
"He's a horse that's always showed us a bit, we earmarked him back as far back as April or May as being a Magic Millions candidate,'' he said.
"He's fit enough to run very well, he will improve off it, but we'd like to think he has the makings of a horse that can find his way up to the Gold Coast.
"He's a nice type, he's a strong, precocious, early type. We'll see where he sits after Saturday but at this stage I wouldn't be swapping him for anything in the race."
If Grebeni lost a few friends when he was beaten in the Festival Stakes two weeks ago Alexiou warns it's not the time to be dropping off as he heads into the Cactus Imaging Handicap (1600m).
The four-year-old, who became the first eligible horse for the 2024 Big Dance with his Goulburn Cup win, conceded a big start in the Group 3 and ran on into sixth behind Phearson and Williamsburg.
"We were happy enough with him, I know he started favourite in the race and a few marked him a bit disappointing but he was a month between runs and paraded a bit fresh,'' he said.
"He's drawn a bit more favourably, hopefully he can settle a bit handier and I'm sure another win isn't far away."
Obviously Alexiou and co-trainer Gerald Ryan know what Grebeni's spring target will be next year but have an open mind about how the next six months play out.
He was a winner at 1800m back in June but Alexiou said the Randwick mile is ideal for him at this stage.
"We're still learning about what his pet trip is. I think he is a horse that will get out over 2000m in time,'' he said.
"If he's positioned well from the barrier he will take plenty of beating."
Sterling Alexiou on Union Army (race 6): "He trialled up well in a slowly run heat. He's always shown ability, barrier one for a big striding horse like him is a bit of a worry but we couldn't be happier with him."
On Smashing Eagle (race 10): "He's a real momentum horse, when you dim his confidence in a race he doesn't find his best. The other day they raced tight around him around the bend, he's a horse that needs a lot of things to go his way and when they do he's never far away."
