Cork City are facing the prospect of a blockbuster Europa League qualifying showdown with Celtic if Brendan Rodgers' men fail to get past Rosenborg in their Champions League clash.
Dundalk, meanwhile, will face the losers of Ajax and Sturm Graz should they get by Cyrpiot side AEK Larnaca in the next round.
The Leesiders were eliminated from Europe's top-tier competition by Legia Warsaw but had the safety net of the Europa League.
Monday's draw in Nyon has paired them with either the Bhoys or Norwegian outfit Rosenborg in the third qualifying round.
The two-legged tie will be played on August 9 and 16, with the first game at Turner's Cross.
Dundalk host Larnaca in the first leg in Oriel Park this Thursday with the return leg fixed for seven days later.
Should they navigate their way through this tie then the reward will be a game against the losers in the Champions League tie between Ajax and Sturm Graz, both of whom finished runners-up in their respective domestic leagues last season.
Scottish champions Celtic face Rosenborg in the second qualifying round of the Champions League; the first leg is on Wednesday.
Rodgers' side coasted past Armenian outfit Alashkert 6-0 on aggregate in their first qualifier, as they look to progress through to the lucrative group stages.
If they do beat Rosenborg they'll face Greek side AEK Athens in the third qualifying round of the Champions League.