Arsenal slumped to a shock 1-0 defeat at Sheffield United as Lys Mousset condemned the Gunners to their latest away-day flop on Monday.
Unai Emery's side are without an away Premier League win since the opening weekend of the season after failing to rise to the challenge posed by fired up United at Bramall Lane.
French forward Mousset, making his first Premier League start for United, punished poor Arsenal defending in the first half to score his second goal since signing from Bournemouth.
That was enough to send Arsenal crashing to just their second defeat of the season, ending an eight-game unbeaten run in all competitions.
The north Londoners sit fifth in the league after a powder-puff performance that showed Emery's rebuilding job is still a work in progress.
Under Emery, Arsenal have kept just two clean sheets in 24 away league matches and once again they wilted too easily in a hostile environment.
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This was a signature win for the Blades after last season's promotion and they sit proudly in ninth place, just three points behind Arsenal.
With the Bramall Lane crowd in full voice, a bruising clash got off to a contentious start when Arsenal defender Sokratis appealed in vain for a penalty after having his shirt tugged by John Egan.
United midfielder John Fleck was fortunate to escape with a yellow card from referee Mike Dean after crunching into Pierre-Emerick Aubameyang. Emery's men should have taken the lead when Sead Kolasinac curled a perfect low cross towards Nicolas Pepe in the six-yard box, but the unmarked Ivory Coast winger completely miscued his shot.
- Pepe struggles -
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