A first-half goal from Wout Weghorst sent Dundalk to a 1-0 Europa League defeat at home to AZ Alkmaar.
Weghorst struck the only goal with nine minutes on the clock, but Dundalk remain in with a chance of qualification.
If they beat Maccabi Tel Aviv in their final group game and AZ do not beat Zenit, they will progress.
On a biting cold night at Tallaght Stadium, much-tested goalkeeper Gary Rogers was Dundalk's stand-out performer.
He was first called upon five minutes in and again moments later during...