Everton were stunned at home in their pursuit of a UEFA Champions League place with a shock 3-2 defeat to Crystal Palace.
After their victory over West Ham on Tuesday, momentum swung back towards Arsenal in the race for fourth place in the Premier League as Everton failed to match their rivals.
The Goodison Park fans would have been expecting an eighth straight home win in the league, but Palace had not read the script, with goals from Jason Puncheon, Scott Dann and Cameron Jerome giving them only a fourth away win of the season.
Palace looked dangerous throughout a frenetic game, in which Everton never got into top gear, and they took a deserved first-half lead through the in-form Puncheon - who notched his seventh goal of the season.
The advantage was doubled shortly after half-time by Dann's powerful header before substitute Steven Naismith halved the arrears with plenty of time remaining.
But Jerome's strike after 73 minutes re-established the two-goal cushion, and although a late Kevin Mirallas strike set up a nervy finish, Everton could not find a way back.
The hosts - who made three changes as part of an attacking line-up, with Ross Barkley, Mirallas and Aiden McGeady all starting - forced the pace from the off, with Gareth Barry stooping to head over from a Leighton Baines corner in the first minute.
Palace, though, soaked up Everton's early pressure and they looked dangerous on the break themselves.
They went closest to breaking the deadlock in the opening stages when, after 20 minutes, Jerome found space unmarked in the penalty area, but his header from Joe Ledley's cross flashed narrowly over the crossbar - although the Palace striker looked to be in an offside position.
The visitors made their pressure count after 23 minutes when Tim Howard could only parry Yannick Bolasie's right-wing cross. The ball fell to Puncheon, who finished neatly from 10 yards, for his fourth goal in the last three games.
It was nearly 2-0 before the interval when a breakaway saw Bolasie hit the base of the post from 30 yards, and an unbalanced Jerome could only put the rebound wide.
Romelu Lukaku then diverted a Barkley cut-back on goal, but Julian Speroni dived smartly to push the ball wide.
Ledley forced a fine save from Howard two minutes into the second half, but from the resulting corner defender Dann's powerful downward header stunned Goodison Park as it beat the unsighted goalkeeper to double Palace's lead.
McGeady almost responded immediately when his fierce 30-yard strike bent narrowly wide of Speroni's left-hand post.
Half-time substitute Naismith did pull Everton back into the game when he converted from close range after Baines had headed a deep Mirallas cross into his path after 61 minutes.
Mirallas then nearly equalised when he met a dipping cross from Baines at the back post, but with 17 minutes left Puncheon was again the architect with superb close control on the edge of the box, sliding the ball into Jerome, who curled into the bottom corner.
Everton refused to lay down even then, and with four minutes left Barkley's throughball was deflected into the path of Mirallas, who rounded Speroni and fired home.
But despite another late chance for the Belgian forward, who mis-kicked with the goal at his mercy, Everton could not find a way back as Palace hung on to effectively end any lingering fears of relegation, and simultaneously blow the race for fourth place in the Premier League wide open.
|Sporting Kansas City 4 Dallas 0: Nemeth, Zusi destroy 10-man visitors|
|Geferson replaces Marcelo for Copa America|
|PSG captain Silva in doubt for Coupe de France final|
|Valverde: Bilbao to stick to style in Copa final|
|´Another round of indictments´ expected in FIFA case|
|Youngsters promoted to Australia´s squad to face Kyrgyzstan|
|Disappointed FFA, US Soccer still want change|
|Gutierrez: Ashley abandoned me|
|US senator urges Blatter to release Garcia Report|
|Gutierrez, Taylor released by Newcastle|
|Figo calls on re-elected Blatter to resign after ´dark day´ for football|
|Szczesny blasts father over ´idiotic´ comments|
|Blatter vows to leave ´strong´ FIFA|
|Blatter re-elected as FIFA president|
|BREAKING NEWS: FIFA elections set for second round of voting|
|Atsu wings in for Bournemouth campaign|
|Klopp: Pokal final not about me|
|Clement says Real goodbyes|
|Inter v Empoli: Icardi looking for final flourish|
|BREAKING NEWS: Blatter - I will fix FIFA|
|Northern Ireland v Qatar: O´Neill keen to prepare for Romania test|
|Palestine drop proposal for Israel suspension|
|Suarez will only get better, warns Iniesta|
|Martinez keen to recruit quickly|
|Monk keen to build on successful Swansea campaign|
|Fit-again Suarez set to aid Barca´s treble quest|
|Anonymous ´bomb´ threat received at FIFA Congress|
|Qatar organisers insist World Cup bid met ´highest ethical standards´|
|Wilkinson and Sorensen leave Stoke|
|Blatter: You can´t ask everyone to behave ethically just like that|
|Van Bronckhorst positive about Feyenoord future|
|Australian police to look into FFA-Warner dealings|
|Dardai signs Hertha deal|
|Protester interrupts FIFA Congress|
|Spurs complete Wimmer signing|
|Warner questions charges following release|
|Mexico v Guatemala: Herrera´s men kick off Copa preparations|
|New Zealand no longer supporting Blatter|
|´Post-World Cup trauma´ affected Mertesacker|
|Racing Club 0 Guarani 0 (0-1 agg): Draw sees Paraguayans through|
|Hamburg shocked by Karlsruher attack - Labbadia|
|Serie A Preview: Napoli, Lazio eye Champions League|
|Hodgson will not overstay England welcome|
|Scholes: United must keep Di Maria|
|Leyton Orient appoint Hendon|
|Benteke has a buy-out clause - Sherwood|
|US Soccer will support Prince Ali in FIFA election|
|Dynamo disappointed with officials after City friendly abandoned|
|Calls for Suarez appeal gather momentum|
|Eredvisie Review: Vitesse denied by late Uth goal, NAC Breda boost survival hopes|
|Rangers 1 Motherwell 3: McCall´s men facing uphill struggle|
|Hamburg 1 Karlsruher 1: Bundesliga side escape with draw|
|Blatter vows to lead FIFA clear of trouble as corruption scandal rolls on|
|Bundesliga: Bayern Munich season review - League crown not enough to signal successful campaign|
|Genoa forced to wait for UEFA licence|
|Injured Cardozo out of Paraguay squad|
|CONCACAF provisionally dismisses Webb and Li|
|Klopp: Career highlights of a charismatic coach|
|Verona v Juventus: Ogbonna seeks strong Champions League warm-up|
|FA charges Demetriou over betting breaches|
|Atalanta v Milan: Inzaghi faces last chance to prove worth|
|King joins Bournemouth as QPR rebuild begins|
|Plymouth part ways with Sheridan|
|Hernandez banned for three matches|
|Chelsea star Fabregas has nose surgery|
|Blatter: More bad news may follow|
|Galliani hopeful over Ancelotti deal|
|Frontzeck to continue as Hannover coach|
|Tremmel released as Tate waves goodbye to Swansea|
|Arsenal v Aston Villa: Sherwood out to upset holders|
|UEFA open to boycott of World Cup - Platini|
|Porto activate release clause for Casemiro|
|Athletic Bilbao v Barcelona: Catalans seeking second leg of treble|
|Auxerre v Paris Saint-Germain: History beckons for Ligue 1 champions|
|Cole confirms West Ham departure|
|UEFA elect not to boycott FIFA Congress|
|Borussia Dortmund v Wolfsburg: Klopp aiming for triumphant farewell|
|Flamini hails Coquelin impact at Arsenal|
|South Africa deny wrongdoing in World Cup bid|
|Benitez confirms Napoli exit|
|McShane among six released by Hull|
|Cerci committed to Milan|
|West Ham expect Collins to return for pre-season|
|Real deny Pogba bid|
|Important to keep Chelsea squad together - Mourinho|
|Alonso: Gerrard was magic|
|Pochettino silent on Ings speculation|
|Visa threatens to ´reassess´ sponsorship amid FIFA scandal|
|Blatter skips FIFA Medical Conference|
|MLS Preview: Revs not out for revenge against Galaxy|
|MLS Review: Sounders go top in West, Timbers and Galaxy win|
|AFC stands by Blatter|
|Matheus ´alright´ after collapse - Markevych|
|Copa Libertadores Review: River, Inter through to semis|
|Signing Toni a ´long shot´ for Adelaide|
|Ramsey good enough for Barca - Coleman|
|Bacuna pushing for Benteke stay|
|Evans stunner settles City friendly in Toronto|
|Banega: Emery a great coach|
|Emery tight-lipped on Sevilla future|
|Argentina finalise Copa America squad|
|Nike issues statement following arrest of FIFA officials|