As Emile Smith Rowe's easy strike hit the back of the net with David de Gea stricken on the ground in front of his unguarded goal, Old Trafford held its breath.
Thirteen minutes into an enthralling encounter between Manchester United and Arsenal, more than 70,000 supporters inside the stadium turned to each other and their phones for clarity, after the most bizarre and controversial goal of the season, possibly in the Premier League's history.
For a moment, the bemusement extended to the stadium's principal television studio wedged between the Stretford End and Sir Alex Ferguson Stand, level with the 18-yard line of the penalty area.