Manchester United goalkeeper Andre Onana was seen jubilantly celebrating his side's opening goal in front of the Arsenal fans - but their lead didn't last long.
Marcus Rashford put United ahead with a superb curling strike from 18 yards, which Aaron Ramsdale got a glove to but couldn't prevent from going into the right corner.
That sparked wild scenes of celebration in the away end, and among United players, who conceded a last-minute winner to the Gunners courtesy of Eddie Nketiah at this stadium last year.
And Onana, who had already had a significant impact on the early proceedings, took the opportunity to jump up and punch the air in front of a section of Arsenal supporters - as most goalkeepers would do after such a huge goal. his celebrations were short-lived, as Arsenal levelled through Martin Odegaard under a minute later.
The Norwegian ran on to a pass from the left side of the penalty area before sweeping the ball beyond the Cameroon international goalkeeper and into the back of the net.
He appeared to berate his team-mates for switching off after the goal went in, urging them to 'calm down' as they went back to take the kick-off.
In the first 15 minutes of the game, Onana completed more passes (12) than any Arsenal player on the pitch, as per Statman Dave, showcasing his distribution qualities once again after impressing in that regard during his opening months as a United player.
But neither goalkeeper made a save during the first half, with both teams going in level at 1-1 in what turned into an evenly-poised fixture on the half hour mark.
Erik ten Hag may choose to turn to new signing Rasmus Hojlund, who is yet to make his debut after joining from Atalanta this summer due to a back injury.
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