Blues bogeyman Costa piles on Arsenal agony
Arsenal 0-1 Chelsea
It just had to be Diego Costa, the pantomime villain who has spent most of the season sulking and under-performing, who delivered the blow which reawakened all of Arsenal's self-doubt and exposed their shortcomings.
Just when Arsenal had the opportunity to bury their Chelsea ghost, to put the belligerent bullies from Stamford Bridge well and truly in their place, they fell short.
Arsenal lost having played the game with 10 men for over 70 minutes following Per Mertesacker's dismissal for fouling Costa.
But then Arsène Wenger's reaction to Mertesacker's red card, by withdrawing Olivier Giroud and persisting with the hopelessly off-form Mesut Özil for 90 minutes, contributed to his team's defeat. It was as though the sight of Chelsea's blue shirts had affected Wenger's thinking and Arsenal's self-belief.
The end result was the defeat which keeps Leicester City on top of the table and left Arsenal with just two points from a possible nine.
Still, Chelsea played like champions once again and, if Arsenal can take anything from this result, it is the reality that the best, regardless of their form or position, rise to the occasion when it matters.
The previous tensions between the two teams ensured that this encounter was never likely to pass off quietly. Chelsea's long-held dominance of this fixture - they are unbeaten against Arsenal in the Premier League since October 2011 - ensured Guus Hiddink's players would fight tooth and nail, regardless of their mid-table position.
Jose Mourinho may have vacated the scene and taken his own particular brand of poison with him.
But the bad blood from last September's clash, when Arsenal ended the game with nine men after the dismissals of Gabriel and Santi Cazorla, has not dissipated with Mourinho's departure and scores were clearly still to be settled.
Throw in the relentless booing of Cesc Fabregas by the Arsenal supporters who once adored the Spaniard and the potency of the cocktail was not in doubt.
It was simply a case of which group of players could handle it better without allowing it to blow up in their faces and, from a very early stage, it was evident that those players were wearing blue.
To say Chelsea have failed to perform this season is something of an understatement, but there was a mood of bloody-minded defiance as they set about denying Arsenal the victory which would return them to the top of the league.
The message from Chelsea was clear: if you are going to take our crown, you are going to have to earn it.
Costa, who was given a three-match retrospective suspension by the Football Association as a result of an off-the-ball spat with Laurent Koscielny at Stamford Bridge, was the most determined of Chelsea's players in terms of defending his honour and he went toe to toe with Koscielny from the off in an effort to impose himself on the French defender.
Koscielny gave as good as he got, but the usually measured Arsenal centre-half allowed Costa to draw him into a physical battle, so the Chelsea man had instantly achieved his primary aim.
The tackles flew in - Koscielny on Costa, Mathieu Flamini on Cesar Azpilicueta, Oscar on Joel Campbell - but Chelsea were enjoying it more than Wenger's players.
And once the dust settled on the physical point-scoring, Chelsea gained control of the game, with Fabregas afforded acres of space in the middle third and Willian enjoying the freedom of Arsenal's left flank thanks to the inability of Theo Walcott and Nacho Monreal to work together to nullify the Brazilian's threat.
It was Willian's pace and vision which led to the key moment of the game, when his through ball to Costa released the forward, only for Mertesacker to bring him down clumsily.
Eighteen minutes into the game, referee Mark Clattenburg had no option but to brandish a red card to the German, whose lack of pace was cruelly exposed by Costa before his trailing leg sent him tumbling to the ground.
Costa again. He is a grade-A pest, a nightmare to play against, but he had got under Arsenal's skin once more and the ramifications of Mertesacker's dismissal were borne out moments later when Wenger chose to substitute Giroud in order for Gabriel to plug the hole alongside Koscielny at the back.
It was a bewildering decision. Giroud, in goalscoring form, would have given Arsenal a physical presence to shield the ball and alleviate the pressure, yet Wenger instead placed Walcott up front before asking Özil to play the role.
John Terry and Kurt Zouma must have shaken their heads in disbelief, especially when Özil plodded into the position, looking like a little boy lost.
And if Gabriel had been sent on to keep Costa quiet, that move backfired too for Wenger, the centre-half losing the Chelsea striker for the crucial split-second as he raced to the near post to volley Branislav Ivanovic's cross past Petr Cech to make it 1-0.
Arsenal's mountain had just grown considerably and Chelsea's supporters gleefully rubbed it in, chanting, "Diego Costa, he's done you again".
Now was the time for the response of champions, the gutsy fightback to hammer home Arsenal's credentials, but with an extra man Chelsea were simply too streetwise and they could have extended their lead when Cech saved brilliantly from Costa at the near post on 42 minutes.
Had Giroud remained on the pitch, Arsenal might have scored themselves three minutes later, but a perfect delivery from Aaron Ramsey was inexplicably directed over by Flamini's kung-fu kick volley, when a header was the obvious option.
Arsenal attempted to salvage the game in the second half and the 57th-minute introduction of Alexis Sanchez injected more urgency and ambition.
But they were only spared the prospect of going 2-0 down when Clattenburg dismissed Chelsea appeals for a penalty after Koscielny had barged Fabregas to the ground. It was reckless challenge, but Koscielny got lucky.
The same could not be said of Arsenal, though, who huffed and puffed until the final whistle without ever truly threatening to score.
Three games without a win now. Is this the annual wobble or a minor bump in the road? It is a question that they really did not want to face at the Emirates.
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