Thomas Vermaelen hit a 95th-minute winner as Arsenal closed to within a point of third-placed Tottenham.
Hatem Ben Arfa put Newcastle ahead with a stylish low finish - but the lead lasted less than a minute.
Theo Walcott fired a cross into Robin van Persie, who scored his 33rd goal of the season with a clinical finish.
Arsenal came from behind to earn victory for the fourth straight game, but tempers flared at the final whistle after Vermaelen's dramatic winner.
Wenger on 'relentless' Arsenal
Van Persie and Newcastle goalkeeper Tim Krul were involved in a confrontation after the goal. The Arsenal striker accused his Dutch compatriot of time wasting in the second half and both players were booked as play spilled into a 98th minute.
It was a riproaring finish to a compelling game as Arsenal continued their remarkable resurgence to keep the heat on their local rivals Spurs, who enjoyed a 12-point cushion over the Gunners just six games ago.
The Frenchman is yet to find the consistency expected of him following his injury problems but he demonstrated in one swift moment why he is so highly rated.
Collecting the ball on the right against the exposed Kieran Gibbs, Ben Arfa cut onto his favoured left foot to drill an angled shot inside the near post - leaving Wojciech Szczesny beaten.
LAST-GASP GUNNERS WINNERS
11 February: 2-1 Sunderland (A)
Thierry Henry (90th minute)
3 March: 2-1 Liverpool (A)
Robin van Persie (93rd minute)
12 March: 2-1 Newcastle (H)
Thomas Vermaelen (95th minute)
The brittle Arsenal of earlier in the season may have crumbled after such an early blow, but they demonstrated their new-found resilience with an equaliser within 60 seconds - and there was no surprises who found the net.
Van Persie's form has been sensational in the past year and the Dutchman took his tally to 44 goals in his last 45 Premier League matches after more good work by the impressive Walcott.
Collecting the England winger's cross from the right, the Dutchman's deft drop of his shoulder left Mike Williamson reeling before drilling a low shot beyond Krul.
After restoring parity, Arsenal controlled much of the possession, but an attritional midfield battle ensued - with Cheick Tiote and Alex Song nibbling away at each other throughout.
Arsenal moved up a gear in the second half, with Tomas Rosicky testing Krul with a glancing header. Alex Oxlade-Chamberlain came inches away with a dipping volley from the edge of the box moments later.
Defeat tough to take - Pardew
Rosicky has enjoyed a renaissance in recent weeks and the Czech midfielder had another impressive game in central midfield but was guilty of a glaring miss halfway through the second half - miscuing his shot from Walcott's cutback.
Arsenal became increasingly desperate for a winner and the introduction of Gervinho added some welcome urgency to the Gunners' attacks. But the Ivorian fluffed his chance of stealing the headlines, scuffing his shot at the far post after Mikel Arteta's free-kick evaded everybody.
The Emirates finally found its voice as Arsenal poured forward in growing numbers to greet a grandstand finish.
Walcott was a continual threat and saw a late shot blocked moments before the fourth official indicated five additional minutes.
Vermaelen came agonisingly close with a header that Krul acrobatically tipped over - but the Belgian was not to be denied moments later as Arsenal continued to fight.
With Newcastle retreating Song picked out Walcott on the right, his cross was only half-cleared to Vermaelen, and the defender swept in from close-range with virtually the last kick of the game.
Theo Walcott is caught offside. Free kick taken by Tim Krul.
90:00 +6:35 Booking
Booking Tim Krul receives a caution.
90:00 +6:25 Booking
Booking Robin van Persie is booked.
The assist for the goal came from Aaron Ramsey.
90:00 +4:08 Goal scored
Goal! - Thomas Vermaelen - Arsenal 2 - 1 Newcastle Thomas Vermaelen scores a goal from close range to the bottom left corner of the goal. Arsenal 2-1 Newcastle.
Laurent Koscielny gives away a free kick for an unfair challenge on Yohan Cabaye. Tim Krul takes the free kick.
Corner taken right-footed by Mikel Arteta, Mike Williamson makes a clearance.
Theo Walcott takes a shot. Fabricio Coloccini gets a block in.
Thomas Vermaelen takes a shot. Save by Tim Krul. Corner taken by Robin van Persie, Shot from just outside the area by Kieran Gibbs goes over the bar.
Hatem Ben Arfa sends in a cross.
Corner taken right-footed by Hatem Ben Arfa to the near post, Robin van Persie makes a clearance.
The ball is swung over by Robin van Persie, Aaron Ramsey takes a shot. Blocked by Danny Simpson. Inswinging corner taken right-footed by Mikel Arteta played to the near post.
Booking Jonas Gutierrez shown a yellow card.
Jonas Gutierrez gives away a free kick for an unfair challenge on Bacary Sagna.
Inswinging corner taken left-footed by Robin van Persie from the right by-line to the near post, Thomas Vermaelen takes a shot. Clearance made by Danny Simpson.
The assistant referee flags for offside against Demba Ba. Indirect free kick taken by Alex Song.
Free kick awarded for an unfair challenge on Robin van Persie by Hatem Ben Arfa. The ball is delivered by Mikel Arteta, Yao Gervinho produces a left-footed shot from deep inside the six-yard box which goes wide of the right-hand upright.
Substitution Cheick Tiote goes off and Danny Guthrie comes on.
Unfair challenge on Bacary Sagna by Shola Ameobi results in a free kick. Bacary Sagna restarts play with the free kick.
Effort from inside the area by Robin van Persie misses to the right of the target.
Yohan Cabaye delivers the ball from the free kick right-footed from left channel.
Booking Booking for Laurent Koscielny for unsporting behaviour.
Foul by Laurent Koscielny on Demba Ba, free kick awarded.
Substitution Tomas Rosicky leaves the field to be replaced by Aaron Ramsey.
Free kick awarded for an unfair challenge on Shola Ameobi by Mikel Arteta. Tim Krul restarts play with the free kick.
Foul by Tomas Rosicky on Jonas Gutierrez, free kick awarded. Tim Krul takes the free kick.
Free kick awarded for a foul by Shola Ameobi on Tomas Rosicky. Kieran Gibbs restarts play with the free kick.
Substitution Yao Gervinho on for Alex Oxlade-Chamberlain.
Tomas Rosicky takes a shot.
Foul by Mikel Arteta on Jonas Gutierrez, free kick awarded. Tim Krul takes the indirect free kick.
Booking Cheick Tiote receives a caution.
Foul by Cheick Tiote on Tomas Rosicky, free kick awarded. Mikel Arteta takes the free kick.
Substitution Shola Ameobi replaces Gabriel Obertan.
The offside flag is raised against Robin van Persie. Free kick taken by Tim Krul.
Shot by Alex Oxlade-Chamberlain from deep inside the penalty area misses to the right of the goal.
Robin van Persie takes a shot. Tim Krul makes a save. Unfair challenge on Cheick Tiote by Alex Song results in a free kick. Tim Krul restarts play with the free kick.
Shot from just outside the box by Theo Walcott misses to the right of the goal.
Robin van Persie takes a shot. Tim Krul makes a save.
Volleyed right-footed shot by Mikel Arteta. Blocked by Cheick Tiote.
Tomas Rosicky challenges Cheick Tiote unfairly and gives away a free kick. Tim Krul takes the free kick.
Foul by James Perch on Theo Walcott, free kick awarded. The free kick is delivered left-footed by Robin van Persie from right wing.
The offside flag is raised against Robin van Persie. Tim Krul restarts play with the free kick.
Shot by Alex Oxlade-Chamberlain from outside the box goes over the target.
The offside flag is raised against Theo Walcott. James Perch restarts play with the free kick.
Tomas Rosicky takes a shot. Save by Tim Krul.
Shot from 35 yards by Cheick Tiote. Save by Wojciech Szczesny.
The match restarts for the second half.
Substitution James Perch is brought on as a substitute for Davide Santon.
45:00 +2:07 Half time
Half Time The referee calls an end to the first half.
Robin van Persie is ruled offside. Indirect free kick taken by Tim Krul.
Jonas Gutierrez concedes a free kick for a foul on Bacary Sagna. Free kick taken by Robin van Persie.
Cheick Tiote concedes a free kick for a foul on Tomas Rosicky. Mikel Arteta takes the free kick.
Inswinging corner taken by Alex Oxlade-Chamberlain, Theo Walcott takes a shot. Fabricio Coloccini gets a block in.
Unfair challenge on Demba Ba by Laurent Koscielny results in a free kick. Yohan Cabaye sends in a cross, Jonas Gutierrez takes a shot. Laurent Koscielny gets a block in. Inswinging corner taken right-footed by Yohan Cabaye from the left by-line to the near post, Robin van Persie manages to make a clearance.
Effort from a long way out by Yohan Cabaye goes wide right of the goal.
Mike Williamson fouled by Tomas Rosicky, the ref awards a free kick. Tim Krul takes the free kick.
Unfair challenge on Theo Walcott by Davide Santon results in a free kick. The free kick is delivered left-footed by Robin van Persie from right channel, clearance made by Mike Williamson.
The referee blows for offside. Wojciech Szczesny restarts play with the free kick.
Bacary Sagna delivers the ball, Fabricio Coloccini makes a clearance.
Bacary Sagna crosses the ball, Danny Simpson manages to make a clearance.
Theo Walcott is caught offside. Free kick taken by Tim Krul.
Fabricio Coloccini gives away a free kick for an unfair challenge on Alex Oxlade-Chamberlain. Robin van Persie produces a shot on goal direct from the free kick, Tim Krul makes a save.
Robin van Persie takes a shot from just inside the penalty box which clears the crossbar.
Robin van Persie is flagged offside by the assistant referee. Tim Krul takes the free kick.
Assist on the goal came from Theo Walcott.
14:08 Goal scored
Goal! - Robin van Persie - Arsenal 1 - 1 Newcastle Robin van Persie fires in a goal from deep inside the penalty box to the bottom right corner of the goal. Arsenal 1-1 Newcastle.
Gabriel Obertan provided the assist for the goal.
13:13 Goal scored
Goal! - Hatem Ben Arfa - Arsenal 0 - 1 Newcastle Hatem Ben Arfa finds the back of the net with a goal from inside the area to the bottom right corner of the goal. Arsenal 0-1 Newcastle.
The ball is sent over by Theo Walcott, clearance made by Fabricio Coloccini. Robin van Persie produces a cross, Theo Walcott takes a shot. Save by Tim Krul.
Cheick Tiote fouled by Tomas Rosicky, the ref awards a free kick. Tim Krul takes the direct free kick.
Robin van Persie concedes a free kick for a foul on Fabricio Coloccini. Tim Krul restarts play with the free kick.
Unfair challenge on Mikel Arteta by Yohan Cabaye results in a free kick. Free kick taken by Mikel Arteta.
Demba Ba concedes a free kick for a foul on Thomas Vermaelen. Thomas Vermaelen takes the direct free kick.
The ball is sent over by Theo Walcott.
Demba Ba takes a shot. Thomas Vermaelen gets a block in. Short corner taken by Yohan Cabaye from the right by-line.
The referee blows for offside. Tim Krul takes the free kick.
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