The defeat by the Blues – which came after the Lions led by 32 points at three-quarter time – ultimately spelled the end of the 2008 finals aspirations of Macdonald and his teammates.
But the hard-working 23-year-old hopes the heart-breaking result may one day represent a watershed moment for the Lions.
"I think having to watch the finals this year on television is going to cut quite a bit more," Macdonald said.
"Last year there was probably a bit of a sense that we were still a fairly young team, that we were improving and that we'd done pretty well to get close to making the finals.
"But this year I think we know that we really could have been there if it hadn't been for a few stupid things like not being able to play a full four quarters when we really needed to.
"Most of the guys, like me, who had played 30 or 40 games last year, have now passed 50 and we've got a much bigger sense of ownership about the team.
"Not playing finals is really going to affect us and should spur us on."
Although this week's clash with the Sydney Swans is effectively a dead rubber, Macdonald says there is no lack of motivation within the Lions camp.
The Lions have beaten five of the top-eight sides this year, but have not beaten the Swans since round one of 2004.
"When we start the 2009 season we'll think back to the last game we've played – and that will be round 22 of this year," Macdonald said.
"The reason you play footy is to get that feeling of relief and joy at the end of the game when you've won.
"Obviously if you are playing in a grand final there is a bit more of a build up but it really doesn't matter what the situation is – that's what you're aiming for.
"We've beaten five of the teams above us and now we've got a chance to make it six and tick another box."
Macdonald will tick some boxes of his own over the off-season by further developing his creative skills in conjunction with "mac&bunno.tv" partner Troy Selwood.
The pair's behind-the-scenes video-logue of life at the Gabba has proven a highly popular new feature on lions.com.au – taking viewers shopping with Simon Black, to the Get Smart premiere on the Gold Coast and also into Selwood's living room for a Nintendo Wii Mario Kart challenge.
Macdonald's previous off-field ventures have included fashion design and DJ'ing. Now, as his best season at senior level winds down, he feels as if the right balance has been struck.
"It's kind of funny – I've always looked for things to do outside of footy because when I first hoped to get drafted everyone told me I was too serious," he said.
"And I was way too serious. In the end I was lucky that I got picked up on the rookie list and got a chance that way.
"It can be hard because when I find something I like to do it 100 per cent and obviously that doesn't always fit in with being a full-time footy player.
"But I think I've finally got the balance right. It's only taken me seven or eight years!"
