The Lions improved to 5-2 with a 17.13 (115) to 10.7 (67) defeat of Fremantle on Saturday at the Gabba, Ashcroft producing a remarkable goal-of-the-year contender among one of his two majors and 28 silky touches.
Lachie Neale was immense with 35 disposals and 15 clearances as Fremantle sunk to 2-5.
But it was the 18-year-old Ashcroft on the tip of everyone's tongue after surpassing his own incredible expectations with a stunning second-quarter effort.
In just his seventh game, the midfielder anticipated the tap from a bounce close to goal, running down the short side and tapping the Sherrin to himself with his right hand.
He regathered in mid-air and, while under pressure, put the ball to the outside of his right foot and somehow squeaked through a goal from the tightest of angles.
The ultra-professional 18-year-old let his guard down, lifting both hands in disbelief and offering a cheeky smile as he was mobbed by his teammates.
Ashcroft's effort likely upstaged teammate Charlie Cameron's similarly freakish goal a week earlier, while it also had a higher degree of difficulty than Daniel Wells' much-celebrated 2004 goal of the year for North Melbourne.
"It was a pretty special goal wasn't it," Fagan said.
"(Wells' goal) wasn't at such an acute angle and not on a checkside.
"If he keeps that (humble) attitude he's going to end up being one of the great players for the Lions.
"There was a bit of a view around football that was a little bit fair I guess, that if you stop Lachie Neale you stop Brisbane.
"We've got a few mores strings in our bow in that midfield area now."
The Dockers lost an 11th-straight first quarter but at least tried to make a dent with daring handballs and aggressive ball movement.
But their hands and composure let them down, two dropped marks and a missed shot at goal spoiling some terrific early ball movement.
That soon fell away too as the Lions found more space, Conor McKenna and Darcy Wilmot combining well as they scooted around the edges of the Gabba square.
Dockers veteran Michael Walters did provide a highlight with his own fantastic goal, spinning out of a tackle and grubbering from the boundary line.
"You can't come up here and be conservative; we wanted to take the game on," Dockers coach Justin Longmuir said.
"We probably got the balance a bit wrong, didn't execute the basics but I liked the dare we showed."
Fremantle's problems are likely to be compounded, Matthew Johnson in danger of suspension after slamming Dayne Zorko into the turf in a tackle that stung the Lion in an otherwise promising game.
Heavily involved in the first half, Zorko was a last-quarter substitution and finished the contest with ice strapped to his hamstring while Daniel Rich was nursing a sore calf.