Beaten in last year's grand final by four points, the Lions find themselves 12th with a 2-4 record, including three losses from three games at their usual Gabba stronghold.
The latest was a wet-weather lesson from Geelong despite the Lions winning contested possessions but hitting the post three times and kicking 13 behinds to just four majors.
Coach Chris Fagan was critical of their over-use, unnecessary handballs inviting pressure after they had worked hard to win the ball.
It was the latest issue in a season that has left the coach scratching his head after losses, but McCarthy has identified a common theme.
"It's hard to put a finger on one thing; each week we see little variables," he said ahead of his 150th game on Thursday.
Brisbane's Lincoln McCarthy celebrates a goal during the 2023 AFL grand-final loss to Collingwood. (James Ross/AAP PHOTOS)
"You've seen a lift in our effort and pressure; we just want to capitalise on those efforts now, bring a bit more composure into our game and really punish sides with the way we move the ball.
"When you're busting out of traffic or (have) broken the tackle, have we given too many handballs before we lower the eyes?
"Can we give an extra handball to a guy with no pressure?
"We still think when we're at our best we can beat anyone. We just have to keep putting that together for longer periods.
"We're giving ourselves that opportunity, now we have to work on executing and converting."
Ultra-talented McCarthy joined the Lions from Geelong in 2019 after five injury-plagued seasons in which he played more than four games just once.
Since then he's barely missed one.
"I didn't think I'd get to 50 ... the original goal was to see if I could get back and play footy again," the father to three boys said.
"I found myself in a bit of a rut, was really questioning whether I was made for the game, to be honest.
"I'm just really grateful for all that support."
Reigning All-Australian captain and Giants star Toby Greene will miss the Canberra clash after failing in his bid to overturn a one-game suspension, with livewire Darcy Jones to debut up forward.
The Lions will be without concussed first-choice ruckman Oscar McInerney, but have regained Irish speedster Conor McKenna.
Ruckman Darcy Fort replaces McInerney, while Jarryd Lyons has been dropped.
