The outcome at Dalymount Park this evening could push one club into Europe and nudge the other closer to the misery of relegation.
But for Bohemians defender Dan Casey, there is no gloating over the state of crisis at his former club, Cork City, who are bottom of the table as the head for Dublin today, having lost a key player, manager and assistant manager all in the space of a dramatic few days.
Cork fans have worries on and off the field, with confirmation this week that a special meeting of the fan-owned club will be held later this month with just one item on the agenda - the sale of the club to Preston North End owner Trevor Hemmings, for just €1.
City chairman Declan Carey admitted earlier this week "that we would not have a football club today" without the cash injection from Hemmings at the start of the season.
Preston bought back the sell-on clauses for former City players Alan Browne and Seán Maguire for a six-figure fee. That money was needed by Cork to clear a debt with Revenue so they could obtain a licence from the FAI to play this year.
Cash-strapped off the field and struggling on it, with just one win in nine games, it's a grim time for Cork who lost manager Neale Fenn and assistant Joe Gamble on Wednesday. Coach Colin Healy is now in temporary charge for their relegation battle.
It's a world away from the scene at Cork at the start of last year when Casey left Bohs to move to Turner's Cross.
"It's sad to see where they are, but I feel they'll have enough firepower to stay up," says Casey.
"I have to put any feelings aside today as I am a Bohs player now, we need the win for our own reasons.
"I don't want Cork to go down as I have friends in that dressing room, but my job is to do well for Bohs.
"It's tough, as a club like Cork shouldn't be at the bottom of the table, talking about relegation.
"They had big ambitions when I joined them last year, they were in Europe and expected to be in Europe regularly.
"I enjoyed my time there and it helped me in my career, it was strange how it turned out in that I left Bohs to join Cork and Bohs did better than we did in Cork last season.
"You can't predict things like that and I have no regrets, Cork made me a better player.
"This season hasn't gone their way and the manager is gone.
"I know Cork City and they will be like dogs coming up to play us today, they have a new manager and they hurting after a couple of defeats.
"Colin Healy is a very good coach, I know that from working with him - and he will have that side well prepared for this game.
"Clubs often get a bounce under a new manager and this is an opportunity for those Cork players to make a statement about themselves. They have a point to prove, with the situation they are in, fighting for their lives."
A win will secure Europa League football in 2021 for Bohs, one of their targets for the season.
"We enjoyed playing in Europe this season and we have a taste for it," says Casey, who is out of contract at the end of the season but is in talks with boss Keith Long about an extension.
Wins in their next two games could see Bohs reduce the lead held by table-toppers Shamrock Rovers to two points before the Hoops play again but Casey does not expect a collapse.
"Rovers are unbeaten in the league for a year so it's hard to see them losing two or three games," he says. "