The Red Devils suffered their joint-worst defeat in the Premier League against a rampant Spurs side at Old Trafford despite having taken the lead from the penalty spot in the first few seconds of the match.
Tottenham responded with quick-fire goals from Tanguy Ndombele and Heung-min Son before the floodgates opened after Anthony Martial was shown a red card.
Moments after the dismissal, Harry Kane put Spurs further ahead and then Son doubled his own tally shortly before half-time, diverting Serge Aurier’s cross between the legs of De Gea.
The Spaniard was particularly upset with that goal and was picked up in pitch-side footage screaming at Shaw for his mistake before punching the goal post.
Shaw had vacated his left-back post which forced Harry Maguire to move out of position to close down Aurier, and despite initially taking up a good spot at centre-back to cover his skipper, Shaw inexplicably ran away from goal.
De Gea could be heard yelling ‘No Luke! No Luke!’ as he sprinted away from the danger, opening up a massive hole for Son to run in to and ultimately score.
The keeper was furious with his left-back after the ball hit the back of the net, screaming, ‘What is your problem!?’ at the 25-year-old and then taking his frustration out on the Old Trafford woodwork.
Shaw fronted up to the media after the game, telling Sky Sports: ‘It was a lack of concentration and then a mistake, another mistake, another mistake. We switched off. It really hurts.
‘Manchester United shouldn’t lose in this manner. It really hurts, it’s embarrassing and we’ve let a lot of people down. We’ve let ourselves down and the staff down.
‘We need to look in the mirror, we are nowhere near it at the moment. Maybe it’s lucky that we’ve got a break now.’