Alexandre Lacazette's opener was overturned by strikes from Ayoze Perez and Matt Ritchie, as Rafa Benitez's side ended a 10-game losing streak against Arsenal and took another huge step towards safety.
Arsenal, though, have now lost five in a row on their travels in the top flight for the first time since December 1984 and are just two points above seventh-place Burnley in the table.
Arsene Wenger, whose primary focus is on the Europa League, started Lacazette and Pierre-Emerick Aubameyang together for the first time and the duo combined to break the deadlock 14 minutes in at St. James' Park.
Perez levelled the scores just before the half-hour mark with his third goal in as many league games, though, after the Gunners failed to deal with a long ball from the impressive Jonjo Shelvey.
Newcastle sensed the chance for a first home league win over Arsenal since 2005 and Ritchie proved to be the hero, finishing in style on 68 minutes to move the Magpies onto 41 points, 13 above the bottom three.
100 - Alexandre Lacazette's goal was the 100th that Arsenal have scored in all competitions this season; the 4th Premier League club to reach this landmark in 2017-18 (after Man City, Liverpool & Spurs). Century. pic.twitter.com/s4R0hVmfmT— OptaJoe (@OptaJoe) April 15, 2018
The Aubameyang-Lacazette partnership bore fruit early on, as the former Borussia Dortmund man latched onto Shkodran Mustafi's long pass and crossed for Lacazette to volley past Martin Dubravka on the slide.
The home side drew level with a similar route-one approach, though. Shelvey's raking pass was cushioned back by Dwight Gayle to DeAndre Yedlin, and his low cross was cleverly steered into the net at Petr Cech's near post by Perez.
Calum Chambers had a great chance to restore the Gunners' lead before the break in very similar fashion to Lacazette's finish, but the full-back could only clip the outside of the right-hand post after stretching to meet Mustafi's header across the box.
11 - Ayoze Pérez's goal ended a sequence of 11 passes by Newcastle United, involving nine of their 11 players - the longest sequence for one of their Premier League goals in 2017/18. Tidy. pic.twitter.com/fG1ZyXHWZR— OptaJoe (@OptaJoe) April 15, 2018
Lacazette spurned another good opening with a poor pass to 18-year-old Premier League debutant Joe Willock, but Arsenal's attacking threat diminished entirely after the break as Newcastle began to push forward.
And it was Ritchie – the man who got the winner against Manchester United in February – who struck the decisive blow, collecting Perez's flick and side-footing past Cech after Nacho Monreal had made a mess of a defensive header.
Kenedy clipped the woodwork on the break but the miss counted for little, with Arsenal's faint top-four hopes all but over as they now face a battle to stay in the top six.
Key Opta Facts:
- Arsenal have now lost 11 Premier League games this season; equaling their worst tally of league defeats in a season under Arsene Wenger (11 in 2005-06).
- This victory for Newcastle United ended a run of 10 successive Premier League defeats against Arsenal – in fact, they won more points today (3) than they had in their previous 12 league games against the Gunners (2).
- All seven of Matt Ritchie's Premier League goals have come in home games (four for Bournemouth, three for Newcastle). Only four players have scored more Premier League goals without scoring away from home than Ritchie (Georginio Wijnaldum, Clive Wilson, Ronny Johnsen and Jeff Kenna).