The club has taken swift action to contain the attack and is currently working with expert advisers to investigate the incident and minimise the ongoing IT disruption," United said in an official statement.
During his time at Old Trafford, De Gea has also established himself as Spain's first-choice goalkeeper and he has enjoyed multiple triumphs with different managers.
"I've got a lot to learn from Pep Guardiola, in the way he pressures referees, talks to opposition players and opposition dugout. He's a fantastic example. I have to learn this. We were angels compared to the other dugout,"
"The incident took place just before the half-time at Etihad Stadium. Aguero had taken an exception to Massey-Ellis signalling for a throw-in for Arsenal," Goal.com reported.
For Tottenham, Harry Kane and Son Heung-min scored two goals each. To make the matters worse, United also lost Anthony Martial in the first half as he was given a red card for an altercation with Tottenham's Erik Lamela.