United lost 4-3 to Bayern Munich in a midweek thriller, but their defence has been leaking goals lately, conceding 14 in their last five matches.
Some players were accused of not working hard enough to help the defence at the Allianz Arena, with Marcus Rashford and Scott McTominay getting some flak.
Stuart Pearce said on talkSPORT that Rashford was running like he ‘had a fridge on his back’ while fans on social media pointed out how McTominay was slower than the referee.
Ten Hag stressed that United need to defend as a unit, saying: ‘It's about 11 players who do their job. I always tell my players we attack with 11 and defend with 11.
‘When one or two are not doing their job, it's like a house of cards, so that is not only one or two players.’
Andre Onana accepted the blame for the defeat in Munich after he let Leroy Sane’s shot slip through his hands for Bayern’s first goal.
But Ten Hag added: ‘It's about team and as a team, we don't have the results in this moment. So also individuals don't bring the performance and you expect not only one player, you include the manager.’