The Magpies never got going and allowed the Gunners to control the tempo of the game for 90 minutes.
Story of the match
A rare goal for Mohamed Elneny put Arsenal ahead after seven minutes.
After a relatively lethargic second half, Pierre-Emerick Aubameyang doubled the Gunners lead after 63 minutes.
Arsenal managed to spread the play quickly which saw Hector Bellerin in space down the right and his cross was tucked him from 12-yards by Elneny.
Newcastle were almost level through Allan Saint-Maximin after 18 minutes as the Frenchman glided past two defenders before seeing his shot superbly tipped over by Matt Ryan.
Just on the half-hour mark, it was Martin Dubravka's turn for a great save as he pushed Granit Xhaka's 20-yard effort behind for a corner.
From the resulting corner, Elneny popped up unmarked on the penalty spot and his header was destined for the far corner, only for Miguel Almiron to head it behind after getting back on the line.
After 38 minutes it was Almiron once again who came to the Magpies' rescue as David Luiz flicked on a corner at the near post but the Paraguayan knocked it behind before Gabriel Martinelli could tap home.
The first of the second half came after 63 minutes as Martin Odegaard picked out Aubameyang unmarked inside the six-yard allowing the skipper to volley into an open net.
The Magpies almost got one back after Sean Longstaff's quick free-kick released Jacob Murphy down the left and his low cross found its way to Jonjo Shelvey whose curling effort was well blocked by Gabriel.
In a moment of madness, substitute Fabian Schar was sent off in the 90th minute for a tackle on Martinelli.
Newcastle too slow on the ball
Far too often Newcastle's midfield were taking three or four touches before passing the ball which allowed Arsenal to get back into their shape.
The midfield duo of Shelvey and Longstaff had worked very well in recent weeks but today they appeared tired and unwilling to risk playing the ball forward without a safe option.
They could bring energy and willingness to take a risk as they have no pressure to perform at their age.
Saint-Maximin is Newcastle's only hope
Something which had been forgotten for the last four games when Saint-Maximin was on top form was that when he's marked out of a game the whole side struggle.
Saint-Maximin managed to get Xhaka booked early on after he fouled the winger twice but in the second half Saint-Maximin hardly got the ball, highlighting the Magpies' problem.
He is usually able to pick the ball up all over the pitch and get Newcastle's forward but the Gunners denied him space and were often tripling up on him when he got the ball.
The Magpies must find a way of getting results when the Frenchman is unable to effect games.