This might be Crystal Palace’s first-ever European campaign but they are learning very quickly. Having arrived in Dublin missing some of their big-hitters including the star striker Jean-Philippe Mateta and the marauding wing-back Daniel Muñoz, they left with a comfortable victory that means they are virtually assured of a place in the Conference League playoffs.

Another three points against the Finnish side KuPS as part of their ­marathon December in which Oliver Glasners’s side play eight matches in three separate competitions should be enough to secure entry directly into the knockout stages after ­slipping up against Strasbourg on their last outing.

But this was an occasion for some of Palace’s fringe players to shine as Christantus Uche capped only his ­second start since joining on an ­initial loan from Getafe in the ­summer with a well-taken goal and Eddie Nketiah scored for the ­second game in succession.

A Shelbourne side that ­finished their domestic season last month were no match even for a largely ­second-string Palace, who had only 15 senior outfield players ­available following the news that Mateta and Muñoz are sidelined with knee injuries.

Thankfully there was no repeat of the unsavoury scenes in France when a minority of Palace fans were ­fighting among themselves before kick-off, although there was a ­banner behind the goal that read “Kick ­racists out of Palace”. Heavy rain in the Irish ­capital greeted the 1,800 who had made the trip from south London, with the game being held at Shamrock ­Rovers’ Tallaght Stadium because Shelbourne’s Tolka Park does not meet Uefa requirements.

This is the first time Shelbourne have ever reached the league stage of a European competition but they had managed only one point and no goals from their first four matches. The manager, Joey O’Brien – the former Bolton and West Ham defender who took over from Damien Duff in July – had urged his players to embrace the occasion in front of a sold-out crowd that included his former Republic of Ireland teammate.

It did not take long for Palace to establish their dominance despite the slippery surface. A flowing move in the 11th minute that was sparked by Daichi Kamada’s clever pass allowed Nketiah to lay the ball on a plate for Uche, who made no mistake with an excellent finish into the far ­corner.

A powerful drive from Adam ­Wharton fizzed over the crossbar three ­minutes later as Palace smelled blood. The lively Nketiah thought that he should have had a penalty when he raced into the penalty area after being gifted possession but the Slovenian referee Martin Matosa waved away his protests.

It wasn’t long until his name was on the scoresheet, the former ­Arsenal striker tapping home from a yard out after Uche had struck the post after being played in by Yeremy Pino. Poor Shelbourne were hanging on for dear life. Kameron Ledwidge was lucky to escape a booking for two ­agricultural challenges on Pino before Chris Richards struck the crossbar from a corner.

The game was effectively over as a contest eight minutes from half-time when Pino meandered past some comically weak challenges into the area and dispatched a shot past the Shelbourne goalkeeper Wessel Speel.

The Spaniard, Kamada and ­Wharton were withdrawn for the ­second half as Glasner took the opportunity to give them a rest, with Will Hughes, Jefferson Lerma and Romain Esse replacing them. The ­latter almost scored with his first touch as Palace were quickly back into their groove but saw his shot blocked. Esse, who has been used sparingly by Glasner since he joined from Millwall last year, couldn’t make more of another decent opening on the hour mark when he scuffed his shot wide.

He was desperately unlucky to see one effort strike both posts before being gratefully clasped by Speel on the goal line. Uche should have at least hit the target seconds later but a glaring miss showed the Nigeria forward is still far from the finished article. There were concerned looks on the Palace bench when Justin Devenny limped off late on as the 17-year-old striker Benji Casey was handed his debut on an otherwise perfect night for Glasner.