Mauro Zarate scored on his debut as West Ham inflicted more misery on Crystal Palace by securing a 3-1 Premier League win at Selhurst Park.
The impressive Zarate was brought into the starting line-up in the absence of injured captain Kevin Nolan and made the most of his opportunity by firing Sam Allardyce's side in front with a sublime volley in an eye-catching display.
Stewart Downing then produced another fine finish two minutes later to put the visitors in command at half-time in Saturday's London derby and Carlton Cole made sure with a third goal after Marouane Chamakh had given Palace hope by pulling a goal back against one of his former clubs.
Defeat for Palace was yet another setback in a turbulent week that saw them fail to appoint Tony Pulis' successor as manager, with Malky Mackay dropping out of contention after allegations were made of inappropriate text messages exchanged between him and Iain Moody during their time at Cardiff City.
Moody subsequently resigned from his role as sporting director at Palace and the club's hierarchy will need to act fast on the evidence of this display, which saw West Ham secure their first top-flight win of the season and leave the hosts without a point.
Palace suffered another blow when they lost Joe Ledley to injury in the warm-up, with Stuart O’Keefe replacing him, but they created the first attack of note when Martin Kelly surged into the penalty area and fired over a cross which drew a fine defensive header from Joey O'Brien to thwart the home side.
Zarate was fortunate to escape punishment for a late challenge on O'Keefe and the Argentine playmaker was then involved in a move which ended with Aaron Cresswell's tame shot being deflected for a corner.
The former Lazio man was causing Palace problems in behind Cole and put the visitors in front with a moment of class 34 minutes in.
Stand-in skipper Mark Noble's shot was blocked and the ball looped into the path of Zarate, who beat Julian Speroni with a stunning right-footed volley from 20 yards out.
Things went from bad to worse for Palace two minutes later when Downing picked up the ball wide on the right and cut in unchallenged before bending a measured finish into the far corner from just outside the penalty area to stun the home supporters.
Tomkins should have added a third goal when he rose to meet Downing's corner and headed against the crossbar just after the break.
And West Ham nerves were sent jangling when Chamakh found space 20 yards from goal before driving a right-footed strike just inside Adrian's right post to give Palace a lifeline.
The home side looked vulnerable at the back, though, and were made to pay for some dreadful defending after 62 minutes as they failed to deal with a free-kick looped into the penalty area and Cole was on hand to finish clinically.
Adrian denied substitute Glenn Murray in stoppage time after some great footwork in the box, but West Ham comfortably saw out a deserved victory to heap more gloom on Selhurst Park.
|Coach: K. Millen|
for F. Campbell 70'
for B. Bannan 71'
for S. O'Keefe 83'
|AFC Champions League: Goalless draws leave quarter-finals on a knife edge|
|Klopp hopeful over Can injury|
|Champions League play-offs: Nine-man Roma crash out as Monaco edge Villarreal|
|Henderson hails ´outstanding´ Mane after Burton thrashing|
|Chelsea 3 Bristol Rovers 2: Conte´s side survive scare thanks to Batshuayi double|
|Hapoel Be´er Sheva 2 Celtic 0 (4-5 agg): Visitors survive Israeli scare|
|Burton Albion 0 Liverpool 5: Sturridge at the double in Reds rout|
|Leverkusen sign Austria star Dragovic|
|Sakho in the clear as WADA opt against appeal|
|Enyimba 3 Mamelodi Sundowns 1: Udoh brace secures CAF Champions League win|
|Pulisic and Ramos on target as Dortmund wrap up Bundesliga preparations|
|Calleri hoping for Tevez advice|
|Defour hoping for Belgium recall|
|Alaba warns against complacency as Bayern begin Bundesliga defence|
|Bravo arrives in Manchester ahead of City move|
|Dyche backs Gray after striker´s apology for homophobic tweets|
|Gray charged by FA over homophobic tweets|
|Pique: Olympic gold proves Neymar is one of world´s best|
|Marin makes Olympiacos move|
|Zidane arrival the catalyst for one of my best seasons - Ronaldo|
|Moyes ´worried´ about Mannone elbow injury|
|Sidibe rejected Arsenal over playing-time fears|
|Guardiola: Toure could feature against Steaua|
|Hernandez out for two weeks after falling down stairs|
|Bravo nearing City move, admits Guardiola|
|Ballack impressed by Dortmund signings but still backing Bayern|
|Lucescu questions De Boer tactics|
|Milan reject Chelsea bid for Romagnoli|
|Dortmund know how to treat Gotze - Ballack|
|Shevchenko: Bacca must improve consistency|
|´If you heed 100 idiots you will go crazy´ - Bauza on Messi return|
|Valdano relieved over Messi U-turn|
|Nordfeldt in line for loan move after signing fresh Swans deal|
|Dante joins Nice from Wolfsburg|
|De Boer expects fierce fight for Barca number-one spot|
|Newell´s confident over Messi return|
|Stoke confirm Jones interest|
|MLS ´attractive´ to Rooney - Timbers owner|
|Burke re-signs with West Ham|
|Sassuolo rejected Balotelli - CEO|
|Valencia coach Ayestaran rules out Mustafi sale|
|Allardyce plans Guardiola talks over Hart|
|Cahill warns rivals over City attack|
|Allardyce open to Terry England return|
|Drogba dismisses Villa rumours|
|Tuchel pleased despite Dortmund wastefulness|
|Stam´s Reading sign Manchester United youngster Blackett|
|Champions League place main objective for Rodgers|
|Eintracht Trier 0 Borussia Dortmund 3: Kagawa at the double as Tuchel´s men stroll|
|Escriba urges cool heads in Monaco|
|Cherchesov sets bar high for Russia|
|Tite defends Neymar´s captaincy credentials|
|Ancelotti wowed by fit-again Martinez|
|Spalletti: If Roma players are afraid, I don´t want them|
|Klopp laments Origi´s absent rhythm|
|Barcelona let Neymar stay in Brazil ahead of qualifiers|
|De Jong brothers joins forces at PSV|
|Rudiger returns to training|
|Liverpool transfer talk frustrates Klopp|
|Klopp demands final third improvements|
|Everton loan Galloway to West Brom|
|Manchester United loan Borthwick-Jackson to Wolves|
|Braithwaite to snub Premier League interest to stay at Toulouse|
|Strachan leaves out McCormack, Rhodes|
|Napoli plan to limit media commitments|
|Taarabt eager to make Marseille switch|
|Kruse suffers knee ligament injury|
|Rummenigge expects Ribery to be targeted|
|Delaney: Benteke is not Messi, he needs service|
|Ballack urges patience with Pep over City project|
|James happy at Real Madrid - Zidane|
|Harper backs Phelan for permanent Hull role|
|Flexibility the key for Allardyce|
|Allardyce concerned over Hart situation|
|De Bruyne praises Sterling reaction|
|Cavani vows to improve strike rate|
|Britton signs Swansea extension|
|Higuain motivated by ´fat´ comments|
|Conte perplexed by Costa criticism|
|Drinkwater poised to sign new Leicester contract|
|Bobo completes Sydney move|
|Bilic: You can´t count on Carroll|
|MLS Review: Dempsey´s Sounders sink rivals Timbers|
|Zidane: Important year for Bale|
|Galaxy star Rogers alleges homophobic abuse|
|Vieira: Pogba just needs to be himself|
|Bacca: I made a promise to Milan|
|Angry Handanovic critical of Inter|
|Gameiro: Atletico must win at home|
|Klopp: I´d be an idiot if I made a panic buy|
|Simeone: Draw leaves a bad taste in my mouth|
|Montella: Milan must win back fans|
|Asensio revels in goalscoring LaLiga debut for Madrid|
|Atletico Madrid 1 Alaves 1: Hosts denied in dramatic finale|