Pedro Neto dealt a fresh blow to spluttering Arsenal's Premier League title challenge as the Chelsea winger's superb strike rescued a 1-1 draw in the London derby on Sunday.
Mikel Arteta's side had taken the lead through Gabriel Martinelli's second-half goal at Stamford Bridge.
But Neto's equaliser 10 minutes later earned Chelsea a deserved point and left the Gunners without a win in their last four league games.
Neto's first Premier League goal since his move from Wolves in August kept third-placed Chelsea above fourth-placed Arsenal on goal difference.
Both teams are nine points behind leaders Liverpool, but while Chelsea will be encouraged by their position after exceeding expectations in Enzo Maresca's first season in charge, Arsenal head into the international break assailed by questions about their malaise.
Beaten 1-0 by Inter Milan in the Champions League on Wednesday, hot on the heels of last weekend's loss at Newcastle, Arsenal have won just three of their last nine league games.
Chasing a first title since 2004 after finishing second to Manchester City in each of the past two seasons, Arsenal lack the fluency that carried them so close to the trophy last term.
The north Londoners' only wins in their last seven matches in all competitions came against Shakhtar Donetsk in Europe and second-tier Preston in the League Cup.
Maresca has repeatedly claimed he does not believe Chelsea are ready to challenge for the title, but the Italian has laid impressive foundations since arriving at the underachieving club in the close season.
Although they were unable to secure a first home win against Chelsea for six years, Maresca's young team appear to be heading in the right direction at last.
Cole Palmer, the jewel in Maresca's crown, quickly forced David Raya into action with a 25-yard drive that the Arsenal keeper tipped over.
Astutely dropping deep to take possession in midfield, Palmer led several Chelsea counter-attacks that had Arteta fretting on the touchline as Malo Gusto's shot was blocked and Noni Madueke's header looped wide.
Gusto should have put Chelsea ahead midway through the first half when Neto teased Ben White with some nimble footwork before whipping in a pin-point cross that the defender somehow headed over from close range.
Frustrated Arteta
Chelsea had imposed their will on Arsenal with a tenacious display featuring some bruising challenges.
But their propensity for overplaying from their own goal kicks nearly proved fatal when Levi Colwill's sloppy pass led to Martinelli forcing a good stop from Robert Sanchez.
Martin Odegaard started his first Arsenal game since August 31 after returning from an ankle injury as a late substitute against Inter in midweek.
Odegaard seemed to have laid on Arsenal's opener when his quick free-kick found Kai Havertz, who slotted past Sanchez in the 32nd minute.
But Havertz's celebrations were curtailed by a VAR check that showed the former Chelsea striker was offside by the narrowest of margins.
Despite that narrow escape, Chelsea had enjoyed a strong spell and they went close to earning a tangible reward when Wesley Fofana volleyed just over from Madueke's cross early in the second half.
Arsenal kept plugging away and snatched the lead on the hour.
Surrounded by defenders on the edge of the Chelsea area, Odegaard cleverly worked just enough space to clip a sublime pass to the unmarked Martinelli and the Brazilian's close-range strike beat Sanchez too easily at his near post.
It was exactly the sort of magical moment that Arsenal had so sorely missed in Odegaard's absence.
Suitably inspired by his captain, Jurrien Timber almost doubled Arsenal's lead with a buccaneering run that end with a low drive that whistled just wide.
But Arsenal's lead was short-lived as Maresca's tactical switch paid dividends in the 70th minute.
Moving Neto from the left to the right flank allowed the Portugal winger to cut inside for a blistering low strike that arrowed into the bottom corner from 25 yards and left Arteta holding his head in frustration.
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