The Republic of Ireland Under-21 side were convincingly beaten by Slovenia in Koper to leave Noel King with an almost impossible task of qualifying for the 2017 U21 European Championships.
Defeat leaves the Boys in Green six points shy of Slovenia in the hunt for a playoff spot, with group 2 leaders Italy a further point ahead with an additional game to play.
The hosts took the lead on 14 minutes when senior international Luka Krajnc turned home a corner at the back post. Ian Lawlor was busy in the Ireland goal as Slovenia sought the security of a second goal, and Ireland's hopes of getting back into the game suffered a setback when Connor Wilkinson was forced off injured.
Substitute striker Sean Maguire looked to replicate his club form with Cork City and did well to force a save from Grega Sorcan with a diving header from Sean Long's cross, but a clumsy foul from Long in the area allowed Maribor striker Gregor Bajde to convert from the penalty spot.
The Boys in Green were handed a lifeline when Callum O'Dowda's shot from range snuck under the goalkeeper, but an expertly taken free-kick saw Miha Zajc restore the two goal cushion and guarantee Slovenia all three points.
King's side face Serbia twice and Slovenia again, needing to win all three matches and hope other results go their way if they are to reach the European Championship finals.