Kenny Jackett admitted he’s still searching for the right Pompey formula.
But the Blues boss underlined a conviction he has the ingredients at his disposal to deliver a winning run to kick-start his side’s season.
They face a Coventry side who’ve won three of their four games amid an unbeaten start to the season.
Now he has to find a way to hit upon fluency in terms of formation and personnel.
Jackett said: ‘I do think that (he’s searching for the right formula), I do definitely think that. There’s a lot to base it on.
‘I don’t think I’m looking at it thinking we’re going to struggle this season and we’re poor.
‘But I don’t think I’ve found the exact formula yet, if you like. On Saturday that did slightly show.
‘I was disappointed how quickly they (Sunderland) got back into it.
‘I was pleased with our start and then they got back into it too quickly, too early and too easily.
‘They didn’t need to work for the goals and then they made it very hard for us to break them down. We have to learn from that.
‘It has to be the case (players know someone can take their place).
‘For us, we have to find the right balance and make sure defensively and offensively we’re strong.
‘We have to find cohesion in our passing and make sure we’re strong enough in both boxes.
‘Set-pieces are such a big part of the game, you’d be a fool to ignore it.
‘We’ll keep working away to find the balance and making sure the squad can win on a consistent basis. We’re capable of it.’
The general display at the Stadium of Light offered plus points, but was undone by slack defending and poor crossing from promising positions.
That’s put the starting positions of Anton Walkes and Ronan Curtis under the microscope ahead of the visit of the Sky Blues.
Jackett added: ‘Our delivery was a big part of our disappointment on Saturday. It’s something which does need to improve.
‘Lee (Brown) and Ronan are on set-pieces and that was very, very poor on Saturday.
‘We had the majority of it and our delivery from Liam and Ronan was poor. It was into the six-yard box for a strong keeper.
‘We talked about the second six-yard box and then the corner went straight into his hands.
‘It was that or we hit it right over everything. We’re disappointed with that.
‘It would be nice to settle the back four down, too, because you do get clean sheets out of it.
The full-backs in my system need to get on and make the play.
‘They need to be athletic, bring the ball forward and create.
‘That’s the modern-day full-back and it certainly is in my system and my way of playing.
‘From our view, we’re looking for that right combination and balance of being defensively solid and creative going forward.’