Porto punished United with 'unnecessary' goals in the eyes of Ten Hag before Harry Maguire, sent on from the bench, salvaged a precious point in this Europa League campaign.
'I don't judge us in this moment. I judge us at the end of the season,' Ten Hag said.
'We are in the process. Just wait. We have to develop this team. We will work and continue. We will fight.'
A goal and assist from Marcus Rashford - who Ten Hag made the strange decision to take off at half time owing to 'rotation' - set United on their way but it was a disastrous evening for Matthjis de Ligt and Lisandro Martinez at the back.
'We scored two great goals but we switched off and we don't keep so much possession as before,' Ten Hag added.
'Defending we switched off, we concede the first goal totally unnecessary then you know you light up the fire in this stadium, this ambience.
'We addressed it at half-time and then you concede the third one so unnecessary, no good defending again. Also again it is some willingness in this moment.
'But then I have to praise the guys for how they return in the game, how they fight to get the equaliser. It's not always about finding it in the last minute, in stoppage time with the set play, but we also had some good chances.'
Maguire refused to be drawn on what this draw means for the future of his manager, but gave his own damning verdict by suggesting United's players have a 'mental issue' when they concede in Europe.
He did, however, suggest that his side have a 'mental issue' when they concede in Europe
'It's more of a mental issue I think, it's about belief,' Maguire, who scored the 91st minute equaliser to make it 3-3, said.
'It's something that we need to be aware of and make sure when we do concede that we stick together and regroup.'
On the future of Ten Hag he added: 'I've played for this club for six years and I know how it works… The manager knows how to deal with it. It's part of the privilege of playing for this club.'