After suffering their first home defeat since April against PSV in their last outing here, AZ were looking for a positive result to also inject some life into their floundering European campaign.
Yet, while they dominated possession throughout the first half here, clear-cut chances came at a premium as they failed to register a single shot on target before the break.
In-form striker Troy Parrott cut a frustrated figure up front as the game passed him by, though it took a brilliant last-ditch interception from Patrick Barrett to deny the Irish international a tap-in on the quarter-hour.
There were very few causes for concern for Joey O’Brien’s visitors, who were the only side to fire a shot on target in the first period, with returning AZ goalkeeper Rome-Jayden Owusu-Oduro smothering Ademipo Odubeko’s effort after a corner dropped to the Shelbourne striker.
After being jeered off at the break, the hosts emerged from the restart with renewed impetus and started to create better chances.
Sven Mijnans slotted through Parrott, who forced Wessel Speel into his first meaningful action with a one-on-one save, before the Shelbourne stopper got down well to parry Mijnans’ long-range effort.
AZ’s lack of cutting edge almost came back to haunt them on 67’ when Odubeko slotted in substitute John Martin on the counter-attack, but Owusu-Oduro reacted well and didn’t allow the Shelbourne striker to round him.
Martin’s lack of conviction was symptomatic of a team who are yet to score in the Conference League this season, and an instant sucker punch was on the way.
An AZ corner was recycled to the edge of the box, where Peer Koopmeiners floated a teasing cross to the back post for Mees de Wit to power home into the far corner and give the hosts the lead.
Seven of the hosts’ previous eight home games had seen both teams score, but Shelbourne’s toothlessness meant a comeback never really materialised.
A brilliant save from Speel prevented Parrott from doubling AZ’s lead late on, but there was nothing he could do to keep out Isak Jensen’s effort from distance in the 87th minute.
That wrapped up a victory that lifts AZ into the top 24, but a third successive defeat for Shelbourne in this competition means their qualification chances are all but over.
Flashscore Man of the Match: Sven Mijnans (AZ Alkmaar)