Fans noticed the 25-year-old star crack a smile before appearing to switch to a sheepish expression when realising the cameras were on him.
Out-of-favour Arsenal goalkeeper Aaron Ramsdale appeared to laugh on the substitutes bench moments after his colleague David Raya committed a howler against Luton.
Raya, who joined on loan from Brentford last summer, has established himself as Mikel Arteta's preferred choice between the sticks at the Emirates, despite making a handful of significant errors since being given the vote of confidence.
Ramsdale, who played all 38 league matches during Arsenal's title pursuit last season, has since dropped to the bench to make way for the Spaniard.
The English shot-stopper appeared in jovial spirits on the Arsenal bench on Tuesday night, as the Gunners carved out a late 4-3 victory at Kenilworth Road thanks to a stoppage time winner from summer signing Declan Rice.
Amazon Prime's TV cameras panned to Ramsdale on the Arsenal bench moments after Raya made his first significant error of the match. Fans noticed the 25-year-old star crack a smile before appearing to switch to a sheepish expression when realising the cameras were on him.
There is, of course, no evidence suggesting that Ramsdale was actually laughing at Raya or his mistake.
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Arteta opted to stay evasive after the match when questioned about whether he was angry with Ramsdale for making two mistakes, opting to frosty reply he was pleased with what he saw.
“I am so happy with the team,” said Arteta.
Arsenal pushed their lead at the top of the Premier League to five points ahead of Liverpool's away clash with Sheffield United on Wednesday.
The Gunners travel to Villa Park on Saturday to take on in-form Aston Villa, who sit fourth in the Premier League ahead of Wednesday's game against champions Manchester City.
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