While the Swans have had a relatively smooth preparation for Friday night's preliminary final at ANZ Stadium, it's been a very emotional build-up for the Magpies, still coming to terms with the death of their former player.
The Swans boss knows how much a personal tragedy can bring a team and club closer together, with Sydney going through their own difficult circumstances last season, with the death of co-captain Jarrad McVeigh's young daughter Luella.
That weekend Sydney went away and beat Geelong, the only loss the Cats have had on their home turf in close to three seasons.
"What I know is football clubs are fantastic things to be a part of when you're going through a grieving process," Longmire told reporters on Thursday.
"We were unfortunate enough to experience something last year that was a really tough period and football clubs are a good spot to be around.
"They really offer a lot of support and no doubt that's what is happening down at Collingwood this week.
"We respect the fact that the McCarthy family have a difficult challenge and the Collingwood Football Club have got a difficult challenge to face today.
"We expect a fierce battle tomorrow night and that's what we're focusing on."
While the Magpies are without skipper Nick Maxwell through suspension and have injury concerns over Chris Dawes (knee) and Alan Didak (calf), the Swans line-up is much more settled.
Midfielder Ben McGlynn will miss the match with a hamstring strain, with defender Heath Grundy the likely replacement as he returns from a one-game ban that saw him miss the qualifying win over Adelaide.
"He was disappointed missing the first final. There's nothing worse than missing a game through suspension at this time of the year," Longmire said of Grundy.
"He's really keen to get out there and looking forward to playing.
"He'll have a big role tomorrow and that's the challenge ahead of him.
"We know he's a good player for us and has been for a long time but he needs to show that tomorrow."
Another key player for the Swans will be livewire Lewis Jetta.
After starring in the early months of the season, the speedster went off the boil in the run-in to the finals but showed signs he was back to his best against the Crows.
"He gave us some real bite around the ground and was back at his running best," Longmire said.
"I enjoyed the tackle when he chased down Patty Dangerfield, I thought that was outstanding, there's not too many blokes who can do that.
"That was a good sign and I think he's back to his real lively best.
"It's great to have a young kid like that who's in the team who understands footy really well and he's enjoying his football."
Longmire said the players were excited about playing in front of a huge crowd at ANZ Stadium and hoped Swans fans turn out in big numbers to help end their 11-game losing streak against Collingwood.
Get out your red and white and get behind the Sydney Swans this Friday night at ANZ Stadium. Click here to buy your tickets
And don't forget to join FANGO for the Brownlow Medal on Monday, September 24 from 7.30pm. Polls, trivia and chat about all things footy, fashion and the count.