Match ends, Newcastle United 1, Arsenal 2.
Granit Xhaka's excellent free-kick set Arsenal on their way to a third consecutive victory under Unai Emery as Newcastle remain without a Premier League win.
Despite being frustrated in the first half, Xhaka opened the scoring for the Gunners with a long-range free-kick that flew past Magpies goalkeeper Martin Dubravka.
As the visitors grew in confidence, Mesut Ozil met the rebound of Alexandre Lacazette's blocked effort to double his side's advantage and ensure Arsenal won consecutive away league games for the first time since May 2017.
Ciaran Clark responded in stoppage time for the hosts, but Newcastle remain 18th in the table with just one win in their past 10 league games.
Rafael Benitez's side remain on one point, equalling their worst return after five Premier League games - although they had much the better of the first-half chances as they pressed an Arsenal defence determined to build from the back.
The early pressure forced errors, as keeper Petr Cech passed the ball out for a corner and defender Shkodran Mustafi's stumble was indicative of an Arsenal back-line still trying to get comfortable with a new style of play under Emery.
However, Arsenal returned the stronger side after the interval and scored twice in 10 second half minutes to secure the points - despite a late Newcastle rally.
Following a tough start to Emery's reign, with opening league fixtures against champions Manchester City and Chelsea, victory at St James' Park is the Gunners third consecutive win and they now appear to be gaining some momentum under Arsene Wenger's successor.
Arsenal, who managed to see off a resurgent Cardiff prior to the international break, knew they would face a stern test against a Newcastle side that had adopted a defensive approach against Chelsea and Manchester City already this season - and were unable to settle into the match as the hosts pressed from the start.
Newcastle's first-half approach demonstrated exactly how to disrupt Arsenal's play under Emery, and both Cech and Mustafi in particular appeared hesitant on the ball under repeated pressure.
But the Gunners were able to take control of the game as the hosts' early energy faded - although it took Xhaka's sublime strike on 49 minutes to really give the visitors confidence.
Arsenal looked comfortable following Ozil's cool finish on his 200th appearance for the club, and were able to see the game out fairly comfortably despite Clark's late reply as Emery's side continued to amend a poor recent away league record that had seen them lose eight of their last 10 prior to kick-off.
And it did appear, once they got into their stride, that Arsenal's players are adapting to Emery's philosophy - although on evidence there remains plenty of work to do.
Benitez's side have been dealt a difficult opening league fixture list this season, having already faced Tottenham, Chelsea, Manchester City and now the Gunners - with only a point against Cardiff to show for their efforts.
In search of a first victory, the manager made four changes to the side that suffered defeat by City prior to the international break, as Jacob Murphy, Matt Ritchie, Isaac Hayden and Joselu were introduced.
Both Murphy and Joselu proved worthy additions as, along with Perez, the home side went about forcing Arsenal into errors in front of a home crowd encouraged by Newcastle's desire to get forward.
In previous games against Chelsea and Manchester City, the Magpies had as little as 19 and 21% possession but - despite falling to a fourth 2-1 defeat by a 'big six' side - there was a definite change in approach as the home side sensed mistakes in the opposition defence.
However the Magpies tired from their earlier exertions and were unable to have the same impact on the match in the second half as Xhaka's moment of quality forced them to chase a result - leaving more space for the Gunners to play.
The winless start must, obviously, be seen in the context of who the Magpies have faced but, as the schedule begins to look more favourable, Benitez will know results must come quickly for his side, who remain in the relegation places.
Arsenal manager Unai Emery: "We are improving. We need to continue working individually and collectively to improve more things. In the first half we didn't control like we wanted but the second half we were better and the victory is just.
"We need to improve and score more individually. We need to work, every player - not only the attacking players but the midfielders and centre-backs from set-pieces.
"For me I see the players are the same, each has quality. His [Ozil's] quality helps the team. It is important he scored. I want not only for him to assist, we need him to go in the box and score like today. I will work with every player and continue our process to create the team as we want."
Newcastle manager Rafael Benitez: "We did really well in the first half. The feeling was we could get something, then we conceded an early goal - two moments of quality and it is difficult for us. The first half was better, we were creating and pushing but you have to take your chances.
"That's what happens when you have quality like they do, it is difficult for anyone. To react against a good team, you have to attack and push higher and you are more exposed. It is a pity, still we are scoring and having chances.
"We knew it could be like that, it is tough. Where we are, we have to keep the belief the same way we did last season."
Newcastle travel to Crystal Palace next Saturday (15:00 BST), while Arsenal's Europa League campaign begins at the Emirates on Thursday night against Ukrainian side Vorskla (20:00 BST).
The Gunners then host Everton on Sunday (16:00 BST).
Match ends, Newcastle United 1, Arsenal 2.
Second Half ends, Newcastle United 1, Arsenal 2.
Henrikh Mkhitaryan (Arsenal) wins a free kick on the right wing.
Foul by Kenedy (Newcastle United).
Foul by Danny Welbeck (Arsenal).
DeAndre Yedlin (Newcastle United) wins a free kick in the defensive half.
Goal! Newcastle United 1, Arsenal 2. Ciaran Clark (Newcastle United) header from the centre of the box to the centre of the goal. Assisted by Federico Fernández with a cross.
Corner, Newcastle United. Conceded by Héctor Bellerín.
Attempt missed. Danny Welbeck (Arsenal) right footed shot from the centre of the box is close, but misses to the right. Assisted by Alexandre Lacazette with a through ball following a fast break.
Corner, Newcastle United. Conceded by Petr Cech.
Attempt saved. Joselu (Newcastle United) header from the centre of the box is saved in the top centre of the goal. Assisted by Ayoze Pérez with a cross.
Offside, Newcastle United. Isaac Hayden tries a through ball, but Joselu is caught offside.
Offside, Arsenal. Shkodran Mustafi tries a through ball, but Alexandre Lacazette is caught offside.
Attempt blocked. Alexandre Lacazette (Arsenal) left footed shot from the centre of the box is blocked. Assisted by Danny Welbeck.
Corner, Arsenal. Conceded by Isaac Hayden.
Corner, Arsenal. Conceded by Ciaran Clark.
Delay over. They are ready to continue.
Substitution, Arsenal. Danny Welbeck replaces Aaron Ramsey because of an injury.
Delay in match Aaron Ramsey (Arsenal) because of an injury.
Substitution, Newcastle United. Yoshinori Muto replaces Matt Ritchie.
Granit Xhaka (Arsenal) wins a free kick on the left wing.
Foul by Mohamed Diamé (Newcastle United).
Foul by Lucas Torreira (Arsenal).
Ayoze Pérez (Newcastle United) wins a free kick in the defensive half.
Sokratis (Arsenal) wins a free kick in the defensive half.
Foul by Kenedy (Newcastle United).
Delay over. They are ready to continue.
Delay in match DeAndre Yedlin (Newcastle United) because of an injury.
Corner, Arsenal. Conceded by Paul Dummett.
Attempt blocked. Henrikh Mkhitaryan (Arsenal) right footed shot from the left side of the box is blocked. Assisted by Aaron Ramsey with a cross.
Corner, Newcastle United. Conceded by Sokratis.
Foul by Henrikh Mkhitaryan (Arsenal).
Matt Ritchie (Newcastle United) wins a free kick on the right wing.
Attempt missed. Lucas Torreira (Arsenal) right footed shot from outside the box is too high. Assisted by Mesut Özil.
Substitution, Newcastle United. Kenedy replaces Jacob Murphy.
Substitution, Arsenal. Henrikh Mkhitaryan replaces Pierre-Emerick Aubameyang.
Foul by Alexandre Lacazette (Arsenal).
Isaac Hayden (Newcastle United) wins a free kick in the attacking half.
Foul by Mesut Özil (Arsenal).
Isaac Hayden (Newcastle United) wins a free kick in the attacking half.