Sports Direct Premiership sides Larne and Linfield and League of Ireland Dundalk and Shamrock Rovers all have major work to do on Thursday if they are to reach the next round of the UEFA Europa Conference League Qualifying stages.
Last week the quartet suffered disastrous results in their first leg clashes in the competition's second round, as Larne lost 3-0 to Ballkani, Linfield lost 5-2 to Pogon, Dundalk lost 3-1 to KA Akureyri, and Samrock Rovers lost 4-0 against Ferencvaros.
As they have the slimmest deficit to overturn, Dundalk are the best-placed of the four sides to make a comeback, and they'll be hoping that home advantage at Oriel Park can see them defeat their Icelandic opposition.
All four goals in the first leg came in the first half, and although Dundalk came away disappointed with the result, manager Stephen O'Donnell was happy with his side's performance and remains optimistic for the second leg.
He told the club's social media channel: "From a performance point of view, I thought it was a totally dominant performance away from home in Europe, and on another day we could have got three or four (goals)."
The Lillywhites will also be hoping that the excitement surrounding the return of Daryl Horgan to the club can help make for a great atmosphere at Oriel, although he will not be eligible for Thursday night's tie.
Kick off is at 7.45pm and the game will be streamed on LOITV.
Also playing with 'home' advantage are Larne, with the game taking place at Solitude.
Tiernan Lynch's side played well below par in the first leg, as they failed to register an attempt on goal away to the Kosovan Super League champions, but if they can get an early goal this evening, belief may begin to stir that they can pull off a comeback.
"The tie can change," goalkeeper Rohan Fergsuon told the club's website. "Goals change games and if we get one back early, you never know what can happen. The tie is certainly not over, that's for sure."
Like Larne, Linfield also have a three-goal deficit to overturn, but they have to travel to Poland, having shipped five goals at Windsor Park last week.
An early penalty goal from former Hull City and West Bromwich Albion midfielder Kamil Grosicki put Linfield on the back foot early, and two second-half goals in the space of four minutes had the Polish side in the ascendancy.
Marisuz Fornalczyk's goal five minutes into stoppage time confirmed a 5-2 win for the visitors and leaves David Healy's side with a mountain to climb this evening.
Kick off is at 5pm local time, and the game will be streamed on 247 TV.
Finally, Shamrock Rovers have the largest deficit to overturn of the four sides having been defeated 4-0 by Ferencvaros in Budapest last week.
A howler from Rovers' goalkeeper Alan Mannus allowed David Siger to open the scoring on 16 minutes, and it was one-way traffic from there, as the Hungarian champions dominated proceedings and had 67 per cent of the ball.
Rovers host the return leg at 8pm this evening in hope more than expectation. Coverage for that game is available on LOITV.