Dundalk suffered a 2-1 defeat to Molde in their Europa League opener at Tallaght Stadium.
Despite going in front in the first-half, Dundalk were undone by their Norwegian opponents.
Molde put huge pressure on the League of Ireland outfit from the beginning.
Patrick Hoban had the ball in the net after a Michael Duffy cross in the 24th minute but it was correctly ruled out as Hoban had fouled a Molde defender in the buildup.
Despite the pressure from Molde, it was the Lilywhites who took the lead 10 minutes before the break.
An inch-perfect cross from John Mountney was converted by Sean Murray.
Dundalk were bouyed by the goal and played some neat attacking football for the remainder of the half, with Mountney and Sean Gannon at the centre of it.
After the break, Molde threw everything at Dundalk in search of an equaliser.
They got what they deserved just after the hour mark as Etzaz Hussain volleyed home a cross from Marcus Pedersen.
The pressure kept coming after that and Molde took the lead from the penalty spot in the 72nd minute.
A clumsy challenge from Gannon saw a Molde attacker go down in the box and Ohi Omoijuanfo made no mistake with the spot-kick.
Dundalk were given renewed hope with seven minutes of additional time, and they looked threatening on a few occasions but couldn't find a crucial equaliser in the end.
The other game in Group B finished on the same scoreline as Arsenal came back to beat Rapid Vienna 2-1 in Austria.
Filippo Giovagnoli's side will travel to London next week to face Arsenal in their next European fixture.