Adrian Bott was at his diplomatic best as Storm Boy matched Sydney-winning stablemate Straight Charge in confirming his Magic Millions 2YO Classic bona fides.

Storm Boy kept an unbeaten record in the Group 3 BJ McLachlan Stakes with a victory that was anything but straightforward for the $1.45 favourite at Eagle Farm.

The colt was slow into stride and was caught wide before jockey Adam Hyeronimus forced the issue to put his mount outside the leader in the $300,000 race.

Despite those nervous moments, Storm Boy established a clear break at the 300m and held his advantage to score a 2-1/2 length win.

Earlier at Randwick, Straight Charge joined Storm Boy as equal favourite for the Magic Millions after resuming with a 3-3/4 length victory but Bott said it was hard to have a preference for one or the other.

"It's difficult to draw a comparison there. We'll find out in three weeks," Bott said.

What is certain is that Bott and training partner Gai Waterhouse have a formidable hand in the $3 million race at the Gold Coast on January 13.

"It's never easy taking on the locals on their turf but he was able to overcome a bit of difficulty, he was strong late and I'm sure there is still plenty of improvement," Bott said.

Storm Boy, by unbeaten American Triple Crown winner Justify, was a $460,000 purchase out of the Coolmore draft at this year's Magic Millions Gold Coast January sale.

He has returned almost $280,000 of that outlay for Cunningham Thoroughbreds with the promise of a lot more to come as Waterhouse chases a record-extending fifth Magic Millions Classic winner.

But Waterhouse and Bott have yet to share glory in the race she first won with Assertive Lad in 2000.

Storm Boy and Straight Charge are the $3.50 equal favourites for the Millions.