Canberra were in imperious form at Central Coast Stadium racing to a 5-0 advantage within the hour mark thanks to doubles from teenager Nickoletta Flannery and Ashleigh Sykes.
American Steph Ochs scored in the first half from the penalty spot, but it was a three-goal salvo inside six minutes just after halftime that did the damage.
It could have been even worse for the Roar, with Canberra's Michelle Heyman incorrectly having a goal ruled out for offside.
Roar claimed consolation in injury time as Emily Gielnik fired home from an acute angle.
It was the first time that two-time champions Brisbane have conceded five goals in the nine-season history of the W-League.
The win was all the more notable given injuries forced Canberra captain Ellie Brush and American forward Jasmyne Spencer out of the starting side.
"We really stuck to our game plan, the ball movement and player movement was really good and we made the most of our chances," said Canberra coach Rae Dower.
"There is a lot of pressure on spots now for the girls we have coming back (from injury)."
In Sunday's other match, Western Sydney Wanderers secured arguably the W-League's biggest-ever upset with a stunning 2-1 comeback win over Melbourne City.
A double from American midfielder Kendall Fletcher gave the unfancied Wanderers victory, despite City scoring inside the opening minutes through Marianna Tabain.
Champions City saw their competition record 18-match undefeated run ended last weekend against fellow title contenders Canberra, but few predicted anything but a one-sided win against a Wanderers side who have never reached the finals.
The result saw City relinquish their hold on top spot for the first time in a season-and-a-half as Canberra and Perth took full advantage to move a point clear, with the former narrowly ahead on goal difference.
On Saturday evening, Matildas star forward Sam Kerr scored a double as Perth Glory continued their strong recent form with a 4-1 win over Adelaide United.