Man United saw their lead cut short by Real Betis in the first half of their Europa League clash on Thursday at Old Trafford.
Ayoze Perez made it 1-1 in the 32nd minute to frustrate the Red Devils.
However, it appears that Juanmi had slightly used his hand to control the ball leading up to the goal.
Some United fans are fuming about this as they reacted on Twitter.
MarkGoldBridge: "Surprise surprise another dodgy handball decision does us over. 100% uses his arm to control that. Disgrace."
Steez: "All the refs need to be replaced with AI this is ridiculous how bad they all are."
UnitedPeoplesTV: "If his arm isn't there, the ball goes in a different direction. Therefore, handball."
Nigel Hayworth: "Can’t even claim it’s accidental when he puts his arm in that position."