Rob Holding flagged alleged racist abuse aimed at the Arsenal bench from a Leeds United fan, with the Premier League launching an investigation.
The first-half of the Elland Road clash on Saturday was marred by alleged racist abuse directed at the Arsenal substitutes.
Holding told the fourth official, who then relayed the information to match referee Andre Marriner - bringing a short halt to the match.
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The league has confirmed an allegation of racist abuse was reported by the visitors, with Mikel Arteta commenting on the incident following his side's comfortable win in Yorkshire.
"It was reported and the stadium manager will have to deal with that with the authorities," he told Sky Sports.
"Very disappointed because we have done so much in football to try to avoid it, but it is a single person. I don't think that merits that a full stadium pays the price.
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"It was a single incident and it has to be reported. It was reported, and now the authorities will have to work with the clubs to understand what happened."
Fans online praised Holding for notifying the officials of the alleged racist abuse.
The Gunners remain in fourth place after winning on the road.
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Arteta's side are on 32 points after beating Leeds 4-1.
Gabriel Martinelli bagged a first-half brace, with Bukayo Saka adding a third before the break.
Raphinha pulled one back from the spot, but Emile Smith Rowe restored his team's three-goal advantage when he finished off a tidy move in the 84th minute.
Topics: Football, Leeds United, Arsenal, Mikel Arteta
