Despite embarking on their first-ever continental campaign, Oliver Glasner's side are learning very quickly. Missing key players like striker Jean-Philippe Mateta and wing-back Daniel Muñoz, the Eagles departed Dublin with a comfortable win that all but guarantees them a spot in the Conference League playoffs.
A further three points in their upcoming fixture against Finland's KuPS should be enough to secure straight entry to the last 16, especially following a prior stumble against Strasbourg.
This match offered a platform for several Palace's fringe players to impress. Christantus Uche, making only his second start since arriving on loan from Getafe, notched the account with a clinical goal. Forward Eddie Nketiah added a another, finding the net for the second game in succession.
A Shelbourne side that had finished their league season proved outmatched even for a mostly rotated Palace lineup. The visitors were already weakened by the reports that Mateta and Muñoz are out with knee problems.
In spite of heavy rain in Dublin, Palace rapidly established dominance. A flowing move in the 11th minute, sparked by Daichi Kamada's clever pass, allowed Nketiah to set up Uche for a simple tap-in.
Midfielder Adam Wharton came close minutes later, fizzing a powerful shot over the bar. Nketiah then claimed for a penalty after racing into the box, but the referee waved away the protests.
Ex-Arsenal striker did not have wait long to get his goal, prodding home from a yard out after Uche's shot had hit the post.
Shelbourne were clinging on desperately. Full-back Kameron Ledwidge was fortunate to escape a booking for a couple of robust tackles on Yeremy Pino, before Chris Richards struck the crossbar with a powerful header from a corner.
The contest was as good as over eight minutes from half-time. Yeremy Pino weaved past a series of comically weak challenges before calmly dispatching a shot past keeper Wessel Speel to extend the lead to 3-0.
Following the break, coach Oliver Glasner seized the opportunity to withdraw several players like Kamada and Wharton. Replacement Romain Esse almost scoring his first touch, only to see his effort blocked.
The youngster was incredibly unlucky later on, seeing one attempt crash off both posts before being clasped on the line. Uche then missed a glaring chance, showing there is still scope for development in his game.
A solitary worry for Palace was a second-half knock to Justin Devenny, who was forced off. This allowed 17-year-old striker Benji Casey to make his first-team debut, capping an otherwise perfect night for the traveling side.