Kenny Jackett told his players they have to handle the pressure of playing for Pompey.
And the Blues boss believes his men have to take steps to avoid anxiety creeping into their game as they look to inject momentum into their season.
Supporters vented their frustration on the final whistle, with the 57-year-old criticised for his decision to send on Christian Burgess in place of Gareth Evans with six minutes remaining.
He said: ‘Portsmouth’s a big club and you have to accept it. You want to be at a big club.
‘We put ourselves in a very good position and unfortunately we didn’t capitalise on it.
‘There was some frustration from the crowd and criticism as well, but when you turn a 3-1 lead into 3-3 you have to accept criticism is coming.
‘Whatever age (the players are) it’s part of pro football.
‘Football is popular so the scrutiny is more.
‘That’s part of coaching, managing and playing. That’s the way it’s always been.
‘We’ve got four points out of four. We were looking for more.
‘I was looking for more and the players looking for more. We wanted a flying start.
‘After a couple of good performances at home we’ve played two of the better sides in the division and got one point from six.
‘For as much as you can analyse the game and what we did or didn’t do it wasn’t our aim.
‘The bottom line is results and points.’
Defensive mistakes have been evident in the past two games, but Jackett knows his players also have to retain the ball better as they prepare to face QPR in the Carabao Cup on Wednesday.
And avoiding the nerves which surfaced at Fratton Park last week is another big factor for the Pompey boss.
Jackett added: ‘You have to realise what you need to do better.
‘For a very good period last season we had several games where we rode our luck and got away with it.
‘If you win those 3-2 nobody says anything and you move on to the next one.
‘We have to accept that when we get into certain position we need more depth, more width and, if we can, work the ball and keep the ball better.
‘We need to keep the ball away from the opposition and quieten it down.
‘We can’t get too anxious, which is easy to say, but we have to do that.
‘After that it’s just nailing the second and third goal. That’s it.
‘Even if you are under pressure make sure you don’t concede.
‘After that we have to realise what he did well at Sunderland and the position we put ourselves into against Coventry.
‘We’ve got quite a good side and need to bridge the gap to turn that into consistent wins.’