Andy Johnson gave a future Palace manager plenty to smile about, but made it a miserable Christmas for former Eagles boss Steve Coppell.
Johnson scored twice and made another for Wayne Routledge as Palace celebrated Monday's impending appointment of Iain Dowie with an outstanding performance.
And an ovation from the travelling supporters for former manager Coppell was scant consolation for the Reading boss, who saw his play-off chasing side turn in a strangely subdued performance.
Johnson had served early notice of his intent as he twice went close in the opening stages.
The former Birmingham striker headed wide when well placed after only three minutes and soon after sent a shot on the turn just wide.
Neil Shipperley wasted an even better chance midway through the first half when he got ahead of Steve Brown but steered his header against a post.
The home side barely created a chance, former Palace winger John Salako fluffing the best of their openings straight into the arms of relieved goalkeeper Thomas Myhre after the offside flag had mysteriously stayed down 11 minutes before half-time.
The best chances continued to flow at the other end and Reading survived another scare when goalkeeper Marcus Hahnemann had to act as sweeper and make two tackles outside his box, before blocking Johnson's follow-up shot with his legs, all following a poor back-pass by Nicky Shorey.
The breakthrough finally arrived on 40 minutes, Aki Riihilahti getting goalside of Steve Sidwell and threading a pass for Johnson to smash home his 12th goal of the season.
The strike continued Johnson's rich run of recent goalscoring form, and he soon showed he could make goals as well as score them as Palace doubled their lead within three minutes.
Johnson raced into space left by forward-thinking full-back Shorey and sent in a low cross for Routledge to roll home from eight yards.
Reading never looked like clawing back from there, though Andy Hughes wasted a good chance when he blazed wildly over after Sidwell had set him up.
And, with only three minutes remaining, substitute Scott Murray forced an excellent save from previously redundant Palace keeper Myhre.
But Palace were well worth their win and Johnson put the icing on the cake in injury-time when he escaped Brown and hit an angled shot across Hahnemann and into the far corner.