Jacob Murphy, Harvey Barnes, Fabian Schar and Alexander Isak were on target for the Magpies on Wednesday, with Marc Guehi also scoring an own goal, as Newcastle made light of the absence of manager Eddie Howe due to pneumonia.
A sixth consecutive victory in all competitions opens up a five-point lead for Newcastle over sixth-placed Chelsea, with a place in the top five good enough for Champions League qualification.
Palace remain down in 12th with their season now fully focused on an FA Cup semi-final date with Aston Villa this month.
Newcastle travel to Villa on Saturday in a huge clash in the battle for European places.
But the League Cup winners are pulling away from the chasing pack for a top-five finish, buoyed by ending their 70-year wait for domestic silverware last month.
“That gave us huge confidence,” said Newcastle assistant manager Jason Tindall, who is was deputising for Howe, of lifting the League Cup.
“We were able to enjoy that for a period of time but we knew what our objectives were for the remainder of the season – to finish as high up the league table as possible.
“The manager always leads and sets that example of never switching off.
“They’ve gone out there, been really consistent and delivering performances.”
Isak wasted two big early chances to open the scoring when he was firstly denied by a fine Dean Henderson save and then headed over from Murphy’s enticing cross.
Newcastle only had to wait until the 14th minute to open the scoring when Murphy blasted in a remarkable finish from a narrow angle. (AFP)
