Arsenal handed the top-four initiative back to Tottenham as they were deservedly beaten 2-0 by an excellent Newcastle on Monday night.
The Gunners struggled with the pressure of the Champions League race after Spurs' victory over Burnley on Sunday and eventually buckled when the returning Ben White turned Joelinton's cross into his own net.
Bruno Guimaraes then sealed the win late on, striking in on the rebound after Aaron Ramsdale had smothered Callum Wilson's shot.
Newcastle impressed during a first half where Arsenal looked nervy, going closest through Allan Saint-Maximin who brought a fine save from Ramsdale at his near post.
The visitors suffered another injury blow to a defence already running on tight hamstrings with Takehiro Tomiyasu's withdrawal, while Newcastle centre back Fabian Schar suffered a similar fate at the start of the second half.
With so much riding on the game, the Gunners struggled to put phases of play together as Newcastle's imposing midfield duo of Guimaraes and Joelinton enjoyed the better of the exchanges.
Arsenal's dreams of a top-four finish then took a massive blow when Newcastle took the lead before the hour.
Joelinton was sent scurrying down the left and pulled the ball across goal looking for Wilson. The England striker couldn't get to it, but White did and prodded it beyond a helpless Ramsdale.
The goal forced Mikel Arteta's hand as Alexandre Lacazette replaced Nuno Tavares, with Gabriel Martinelli previously coming on for Emile Smith Rowe, but it was Newcastle who had the next best opportunity. Guimaraes picked out Wilson, but his first-time volley sailed clear of the bar.
Arsenal were largely reduced to potshots from distance as Eddie Howe's side enjoyed the better opportunities. Substitute Nicolas Pepe gave the ball away to send Jacob Murphy and Ryan Fraser through on goal, but the pair couldn't combine well enough and Ramsdale made the save.
The Gunners finally caused some disarray in the Newcastle box within ten minutes of the final whistle, though some heroic defending ensured Martin Odegaard's fierce strike made it nowhere near goalkeeper Martin Dubravka.
The pressure didn't tell, however, and Newcastle got a deserved second close to full time. Wilson couldn't quite latch onto Sean Longstaff's pass, but the rebound fell for Guimaraes to convert despite Cedric's last-ditch attempted clearance.
The result means Arsenal will have to beat Everton on the final day of the season and hope Norwich defeat Tottenham. Spurs' goal difference is vastly superior, so the Gunners will have to overturn the point deficit on Sunday.
A top half finish is still possible for Newcastle, though they'll need to beat Burnley and hope both Brighton and Brentford suffer poor results.
Newcastle vs Arsenal player ratings
1. Newcastle (4-3-3)
GK: Martin Dubravka - 6/10 - Rarely called into action by Arsenal's misfiring forwards.
RB: Emil Krafth - 6/10 - Solid and repelled most of what Arsenal threw at him.
CB: Fabian Schar - 6/10 - Had a solid first half but suffered a worrying knock to the head at the start of the second half and had to come off.
CB: Dan Burn - 7/10 - His height could have been utilised more with the number of set pieces Newcastle had. Played a good role in the second role with a nice pass.
LB: Matt Targett - 6/10 - Not always the most convincing on the left but did his bit.
CM: Sean Longstaff - 7/10 - Nice and combative in midfield, making more tackles than his Brazilian colleagues. Nice pass in the build-up to the second goal.
CM: Bruno Guimaraes - 9/10 - Great on the ball and intense in defence. Got a deserved goal towards the end with a composed finish.
CM: Joelinton - 8/10 - The most physically imposing midfielder on the pitch. Kept the ball well and got on the half-turn nicely. Surging run and cross set up White's own goal.
RW: Miguel Almiron - 7/10 - Got through a good amount of defensive work and looked fluid in the attacking moments he had.
ST: Callum Wilson - 6/10 - Put pressure on White to divert beyond his own goalkeeper. Had a few opportunities to score but a decent return to the starting XI.
LW: Allan Saint-Maximin - 7/10 - Came closest to breaking the deadlock, testing Ramsdale at his near post. Played a lovely ball to Joelinton for the goal.
SUB: Jamaal Lascelles - 6/10 - Marshalled his defence well after coming on for Schar.
SUB: Ryan Fraser - 5/10 - Butchered a one-on-one with fellow sub Murphy.
SUB: Jacob Murphy - 5/10 - Had an excellent chance for 2-0 but had his strike saved.
SUB: Dwight Gayle - N/A
2. Arsenal (4-2-3-1)
GK: Aaron Ramsdale - 6/10 - Decent stop to deny Saint-Maximin the opener. One save on the counter from Murphy which kept Arsenal in the game. Another fine stop at the end.
RB: Takehiro Tomiyasu - 6/10 - Solid enough before tweaking his hamstring and needed to be brought off for Cedric in the first half.
CB: Ben White - 4/10 - Went into the book for a foul on Wilson. Could only stick it past his own goalkeeper from Joelinton's cross.
CB: Gabriel - 5/10 - Not particularly authoritative in the face of some fierce Newcastle attacking.
LB: Nuno Tavares - 4/10 - Pretty flimsy in defence and offered little in attack before coming off as Arsenal chased the game.
CM: Mohamed Elneny - 4/10 - Struggled to exert any authority in the middle of the pitch.
CM: Granit Xhaka - 5/10 - Couldn't deal with the physicality and intensity of Guimaraes and Joelinton. Later shuffled over to left back.
RW: Bukayo Saka - 5/10 - Combined with Odegaard on occasion but largely ineffective.
AM: Martin Odegaard - 6/10 - Got on the ball as Arsenal tried to create, dropping deeper as the game progressed.
LW: Emile Smith Rowe - 4/10 - Came on for Gabriel Martinelli but had little influence in the opening 45. Brought off soon after for Martinelli.
ST: Eddie Nketiah - 5/10 - Failed to get any shots away in the first half despite getting into some half promising positions. Booked for hitting Schar at the start of the second period.
SUB: Cedric Soares - 4/10 - Despairing dive on the line couldn't prevent Guimaraes' strike rolling in.
SUB: Gabriel Martinelli - 4/10 - Just couldn't inject any life into Arsenal's attack.
SUB: Alexandre Lacazette - 4/10 - Had no opportunities to shoot at goal.
SUB: Nicolas Pepe - 3/10 - Created a goalscoring opportunity soon after his arrival, though it was for Murphy at the other end with a shocking pass.