Brian Barry-Murphy believes Pompey have taken things to another level this season.
But the Rochdale boss insisted his side won’t play on the back foot at Fratton Park.
The Dale travel to the south coast tomorrow with plenty at stake for both sides.
The Blues are pushing for automatic promotion from League One and are currently three points behind second-placed Sunderland.
In contrast, Rochdale are scrapping to save their status in the division, sitting just two points above the relegation zone.
After an eighth-place finish last term, Barry-Murphy feels Kenny Jackett’s men have made massive strides this campaign.
Rochdale are firm underdogs heading into the clash and have the worst defensive record in the Football League.
But the manager vowed the Dale won’t be fighting a rearguard action on the south coast.
‘They were strong last season but I think this season they’ve taken it to a different level,’ Barry-Murphy told his club’s website.
‘They have a hugely-experienced manager and it is a fantastic club.
‘It is going to be a huge test for us in terms of the game itself on Saturday.
‘But we are very excited to go and visit.
‘The lads are keen to put on a performance we think we can implement and cause them some problems, which is our aim.
‘We don’t aim to go there and defend or be on the defence all of the game.
‘We aim to be on the attack when we can.
‘We realise that won’t be possible all of the time but we will attack when we can.’
Pompey have already delivered two victories over Rochdale this season.
Jackett’s side picked a 3-1 League One success at Spotland in September, before winning the FA Cup second-round tie three months later.