Nolberto Solano's late winner eased the pressure on Newcastle boss Graeme Souness in a stormy clash with Arsenal.
Arsenal totally dominated the first half, with Shay Given denying Thierry Henry with a brilliant save.
But Newcastle's physical approach rattled the Gunners after the break and Gilberto was sent off after 56 minutes for two bookable offences.
And Newcastle's spirited display earned victory when Alan Shearer set up Solano to fire home with nine minutes left.
Newcastle were able to recall Michael Owen following a four-game absence with a groin injury, but he got little chance to shine in a first 45 dominated by Arsenal.
Arsenal had penalty appeals waved away after 14 minutes when Gilberto's shot struck the arm of Titus Bramble, but referee Dermot Gallagher ruled that it was accidental.
Newcastle goalkeeper Given then produced a magnificent save to deny Henry, who met Fabregas' cross with a crisp volley.
Henry missed a good chance after 28 minutes when Freddie Ljungberg's cross found him at the far post, but he appeared to be unsettled by Jean-Alain Boumsong's presence and failed to control.
Newcastle may have been short on quality, but they were demonstrating plenty of fighting spirit, which Amdy Faye took too far before half-time when he was booked for a late tackle on Philippe Senderos.
Scott Parker made a rare raid into Arsenal territory in the dying seconds of the first half, but his low cross eluded Owen and Shearer.
Newcastle were a team transformed after the interval, knocking Arsenal out of their smooth stride with a fierce physical assault.
Parker fired off target from Shearer's pass - then Newcastle's captain did likewise when the midfield man repaid the compliment.
Arsenal had lost their composure, and their troubles increased after 56 minutes when Gilberto was sent off for a second bookable offence when he clumsily brought down Boumsong.
The Gunners were then rightly furious when Shearer escaped any punishment for a wild lunging tackle on Sol Campbell - an incredibly lenient decision given what had gone before.
Parker had been outstanding for Newcastle, and he almost broke the deadlock with a long-range drive.
But he then appeared to suffer damage to his teeth in a collision with Arsenal keeper Jens Lehmann. He struggled on bravely but eventually had to be substituted, with Lee Bowyer coming on.
The game had undergone a remarkable transformation, and it was no surprise when Newcastle took the lead with nine minutes left.
Shearer's physical presence again unsettled Arsenal, and he laid the ball into the path of the Peruvian, who fired a right-foot finish across Lehmann into the corner.
In keeping with the atmosphere, there was even a bust-up between Fabregas and Shearer before the re-start.
Shearer was finally booked in the dying seconds for a foul on Senderos, punishment Arsenal had every justification to feel was long overdue.
Newcastle survived five minutes of injury time to record a crucial win.
Newcastle assistant coach Dean Saunders:
"It's the Premier League and we have got players in the team like Amdy Faye, Scott Parker and Alan Shearer who like tackling and like competing.
"The team likes to compete and today we played to their strengths, we got forward and we upset Arsenal.
"That's what we set out to do today, we set out to stop Arsenal playing. I don't think it was a nasty game."
Arsenal boss Arsene Wenger:
"I think it's very difficult to take the way we lost the game. We were the better team in the second half, they decided to go more physical..
"The referee allowed more fouls, sent a player off for us and I don't know why.
"We played well and I just believe we were not protected - every challenge in the air was a foul. We know Alan Shearer can do that in this country."
Newcastle: Given, Ramage, Boumsong, Bramble, Elliott, Solano, Faye, Parker (Bowyer 74), Ameobi, Shearer, Owen (Chopra 90).
Subs Not Used: Harper, Luque, Brittain.
Booked: Faye, Shearer.
Goals: Solano 82.
Arsenal: Lehmann, Toure, Senderos, Campbell, Lauren, Ljungberg, Fabregas (Pires 86), Silva, Hleb (Flamini 63), Van Persie (Owusu-Abeyie 85), Henry.
Subs Not Used: Almunia, Eboue.
Sent Off: Silva (57).
Ref: D Gallagher (Oxfordshire).