On that occasion, the Kangaroos blew the Lions away early to lead by 33 points at quarter time and were never troubled in winning by 63.
It was arguably the Lions' worst performance of the season.
Co-captain Adcock says although the Lions are a vastly improved team since then, they have reflected on that poor showing.
He said it had little to do with style and structures, and more to do with brute force.
"It's more about attitude … intent to put your head over the footy," Adcock said.
"Our first six weeks was disappointing. We rectified a few things to where we are now. We're in a much better place."
The Lions will be without Brent Moloney (calf) and are also likely to be missing Simon Black (groin) for a second straight week, and Mitch Golby (bruised lung).
Both were restricted to stationary drills during the early stages of Wednesday's closed training session.
Adcock said the main focus for the Lions this week had been starting fast, against a Kangaroos outfit that was 12-2 in first quarters this season.
Conversely the Lions are the worst first quarter team in the competition, leading just three times at the first change.
Both teams are mathematical chances of making the top eight, but Adcock said the Lions had to worry about beating teams around them on the ladder before contemplating action in September.
"Gold Coast was above us on the ladder, around us, so that was a good start," he said.
"That's the gap we have to close.
"We've had a couple of upsets against Geelong and Essendon, but the gap between us is where we've got to close.
"It's probably been similar for a few years. We haven't been making that headway into the group above us. It's got to change some time. Hopefully we can change it this week."
