Gabriel Martinelli scored Arsenal's second just 93 seconds after stepping off the bench
Arsenal eventually broke Newcastle United down to leave Eddie Howe's side bottom of the Premier League without a win.
Howe, in the Magpies dugout for the first time after missing last weekend's 3-3 draw with Brentford because of Covid, set up a team to try to contain Arsenal and eke out a point.
It appeared as if the strategy might be working until Bukayo Saka slotted home from Nuno Tavares' through ball in the second half.
Saka went off injured and his replacement Gabriel Martinelli scored with his second touch, a wonderful volley from Takehiro Tomiyasu's clipped pass over the top.
"He wasn't comfortable. He felt something," said Gunners boss Mikel Arteta of Saka as they await news of what is wrong with the England international.
Both sides had hit the woodwork in an otherwise uninspiring first half.
Jonjo Shelvey's long-range drive was tipped on to the bar by the diving Aaron Ramsdale - and Pierre-Emerick Aubameyang hit a sitter off the post from six yards out.
Arsenal remain fifth in the Premier League, while Newcastle are five points adrift of safety with just over a third of the season gone.
- Follow live text coverage of Saturday's Premier League actionGo to the Arsenal pageGo to the Newcastle page
A lot to do for Howe and Newcastle
Newcastle are on their longest ever winless run from the start of a league season. Only one side has ever stayed up in the Premier League after failing to win their opening 13 games - Derby County in 2000-01.
The Magpies know the further adrift they are on 1 January, when they have a chance to spend some of their Saudi owners' money, the harder it will be to attract quality players.
It is unlikely though that Howe will have identified Emirates Stadium as a place to pick up points. The Gunners have won their past 10 home games against Newcastle in all competitions, and have never lost a Premier League home game against the team bottom of the table.
The side he put out looked attacking on paper but on the actual pitch they sat in and tried to frustrate Arsenal.
Shelvey was their main threat when they went forward with five of their nine efforts on goal, including a fine strike tipped on to the crossbar by Ramsdale.
Callum Wilson was isolated up front, with only 13 touches, but he felt he should have had a penalty when he was nudged over by Tavares in the box - moments before Arsenal's second goal.
The Gunners' quality eventually showed when Saka finished off a nice passing move, which also involved himself, Emile Smith Rowe and Tavares.
Martinelli's glorious volley past the onrushing Martin Dubravka - making his first Newcastle appearance of the season - wrapped things up.
Arsenal are back to winning ways now, after last weekend's 4-0 thrashing by Liverpool ended a 10-game unbeaten run.
They should have won by more, with 23 shots - including Aubameyang hitting the upright after Dubravka had parried Smith Rowe's header when a goal looked inevitable.
Next up for Newcastle are two huge ones - home games against Norwich City and Burnley, the other two teams in the relegation zone. They will have to face the Canaries without captain Jamaal Lascelles and Matt Ritchie, who both picked up their fifth bookings of the season at the Emirates.
Player of the match
with an average of 8.48
- ArsenalArsenalArsenalNewcastleNewcastle UnitedNewcastle United
ArsenalAvgSquad number32Player nameRamsdaleAverage rating
Squad number7Player nameSakaAverage rating
Squad number35Player nameGabriel MartinelliAverage rating
Squad number18Player nameTomiyasuAverage rating
Squad number10Player nameSmith RoweAverage rating
Squad number4Player nameWhiteAverage rating
Squad number6Player nameGabriel MagalhãesAverage rating
Squad number20Player nameNuno TavaresAverage rating
Squad number23Player nameSambi LokongaAverage rating
Squad number8Player nameØdegaardAverage rating
Squad number5Player nameParteyAverage rating
Squad number9Player nameLacazetteAverage rating
Squad number25Player nameMohamed ElnenyAverage rating
Squad number14Player nameAubameyangAverage rating
Newcastle UnitedAvgSquad number1Player nameDúbravkaAverage rating
Squad number10Player nameSaint-MaximinAverage rating
Squad number28Player nameWillockAverage rating
Squad number8Player nameShelveyAverage rating
Squad number9Player nameWilsonAverage rating
Squad number24Player nameAlmirónAverage rating
Squad number23Player nameMurphyAverage rating
Squad number5Player nameSchärAverage rating
Squad number11Player nameRitchieAverage rating
Squad number7Player nameJoelintonAverage rating
Squad number14Player nameHaydenAverage rating
Squad number21Player nameFraserAverage rating
Squad number17Player nameKrafthAverage rating
Squad number6Player nameLascellesAverage rating
- Line-upsMatch StatsLive Text
32Ramsdale18Tomiyasu4White6Gabriel20Varela Tavares7Saka5Partey23Sambi Lokonga10Smith Rowe8Ødegaard14Aubameyang
- 32Ramsdale18Tomiyasu4White6Gabriel20Varela Tavares7SakaSubstituted forMartinelliat 64'minutes5ParteySubstituted forElnenyat 85'minutes23Sambi Lokonga10Smith Rowe8Ødegaard14AubameyangBooked at 76minsSubstituted forLacazetteat 76'minutes
- 1Dúbravka17KrafthBooked at 48mins6LascellesBooked at 63mins5Schär11RitchieBooked at 44minsSubstituted forAlmirónat 67'minutes21Fraser8ShelveySubstituted forHaydenat 89'minutes28Willock10Saint-Maximin9Wilson7JoelintonSubstituted forMurphyat 67'minutes
- 2Clark12Lewis14Hayden16Hendrick19Manquillo23Murphy24Almirón26Darlow36S Longstaff
Referee:Stuart AttwellAttendance:59,886Match StatsHome TeamArsenalAway TeamNewcastlePossessionHome66%Away34%ShotsHome24Away9Shots on TargetHome6Away5CornersHome4Away4FoulsHome6Away12Live TextPost update
Match ends, Arsenal 2, Newcastle United 0.
Second Half ends, Arsenal 2, Newcastle United 0.
Corner, Newcastle United. Conceded by Aaron Ramsdale.
Benjamin White (Arsenal) wins a free kick in the defensive half.
Foul by Callum Wilson (Newcastle United).
Attempt missed. Gabriel Martinelli (Arsenal) right footed shot from the right side of the box misses to the right. Assisted by Takehiro Tomiyasu.
Substitution, Newcastle United. Isaac Hayden replaces Jonjo Shelvey.
Attempt blocked. Emile Smith Rowe (Arsenal) left footed shot from outside the box is blocked. Assisted by Mohamed Elneny.
Attempt saved. Allan Saint-Maximin (Newcastle United) right footed shot from the left side of the box is saved in the bottom right corner. Assisted by Fabian Schär.
Substitution, Arsenal. Mohamed Elneny replaces Thomas Partey.
Attempt saved. Joseph Willock (Newcastle United) right footed shot from the left side of the box is saved in the top left corner. Assisted by Allan Saint-Maximin.
Attempt missed. Alexandre Lacazette (Arsenal) left footed shot from the left side of the box is close, but misses to the left. Assisted by Gabriel Martinelli following a fast break.
Attempt blocked. Jonjo Shelvey (Newcastle United) right footed shot from outside the box is blocked. Assisted by Jacob Murphy.
Offside, Newcastle United. Ryan Fraser tries a through ball, but Fabian Schär is caught offside.
Substitution, Arsenal. Alexandre Lacazette replaces Pierre-Emerick Aubameyang.
Pierre-Emerick Aubameyang (Arsenal) is shown the yellow card for a bad foul.
Foul by Pierre-Emerick Aubameyang (Arsenal).
Miguel Almirón (Newcastle United) wins a free kick in the attacking half.
Corner, Newcastle United. Conceded by Gabriel Magalhães.
Attempt blocked. Fabian Schär (Newcastle United) right footed shot from outside the box is blocked.
Page 1 of 5rewindpreviousNavigate to the next pagenextNavigate to the last pageforward
- Our coverage of your Premier League club is bigger and better than ever before - here's everything you need to know to make sure you never miss a moment