Andros Townsend, Yohan Cabaye and Luka Milivojevic scored the goals to drag the Eagles six points clear of the relegation zone, and almost certainly ensure Sam Allardyce’s unblemished record of Premier League survival endures.
But the empathic defeat ought to lead to renewed debate over the future of not only Arsene Wenger but a host of Arsenal’s most important players. Seventy-million-pound summer signings Shkodran Mustafi and Granit Xhaka hampered their team’s cause while the likes of Mesut Ozil and Theo Walcott were ineffectual.
Arsenal must now make up seven points to reach the top four with a game in hand but a 20th consecutive season of Champions League football looks some way beyond them.
Neither Wenger nor Allardyce shuffled their pack from the midweek round of games despite differing fortunes, yet few observers in the first half would have thought that it was Crystal Palace coming into the game off the back of a dispiriting defeat.
Not that Arsenal were necessarily poor in the first half but Palace were exceptional, led by the Christian Benteke of his Aston Villa days, a forward too physically imposing yet subtle on the ball for Shkodran Mustafi.
The World Cup winner was not the only Arsenal player to struggle with Palace’s aerial presence. As early as the third minute Mamadou Sakho found himself marked by Hector Bellerin off a free-kick, from which the Liverpool loanee teed up Yohan Cabaye to strike over.
Next time Palace had a free-kick like that it was Theo Walcott picking up Sakho. The lessons of last month’s 3-1 defeat at West Brom had not been learned.
Though Palace merited their first-half lead there was plenty of fortune in it. Benteke won a long-ball almost uncontested by Gabriel. Palace had an overload on the right, where Cabaye fed Wilfried Zaha.
The Ivorian international slipped as he fired in his cross but that mistake put the ball right into the path of the onrushing Andros Townsend. The boyhood Tottenham fan unquestionably enjoyed the opener.
From then on Arsenal monopolised the ball, they had seen 72 per cent of it by the half-time whistle, and created chances, though most of them involved shots through a forest of Palace bodies.
On the occasions when those efforts found their way through to goal Wayne Hennessey was on hand to turn the ball away, most impressively from Mohamed Elneny seven minutes before Townsend’s goal.
That lead played perfectly into Palace’s hands, allowing them to use Benteke as the battering ram for their counters.
His power was too much for Mustafi, whose booking would have come well before the 22nd minute were it not for the generosity of Michael Olivier.His delicacy only made him more threatening and the Belgian international deserved a goal when he found space inside the area to take a pass from Wilfried Zaha.
The impressive Emiliano Martinez was on hand to parry that strike, ensuring Arsenal reached the break in the hunt.
It got no easier for the visitors after the interval and Palace ought to have doubled their lead on 51 minutes. A fizzing Townsend shot was pushed only as far as Benteke by Martinez. The offside target man tapped into an empty net. Had he left it for Jason Puncheon it would have been 2-0.
It wasn’t long before the two goal lead was realised though. Moments after Wenger had brought on Olivier Giroud and Aaron Ramsey for the Danny Welbeck and Mohamed Elneny, both ineffectual, Zaha found space on the edge of the box as Nacho Monreal unconscionably backed off his man.
Again the cross may have been miscued as Zaha slipped but there was nothing fluky about Cabaye’s looping finish over Martinez from the edge of the area.
If character shines through in adversity then Arsenal’s response encapsulated all of their essential flaws. Giroud appealed for a penalty that he had no right to win.
Then Martinez carelessly conceded a spot kick of his own, giving Townsend a chance to go down easily as both chased a loose ball. The exceptional Milivojevic got the goal he deserved from the spot.
With this exceptional win Palace are surely bound for safety. Any Arsenal manager other than Wenger would feel anything but safe after a performance as pitiful as this.