Tom Naylor has insisted Pompey are striving for the best defensive record in League One.
Kenny Jackett’s side have conceded just 14 goals from their opening 16 matches this season, keeping five clean sheets.
The Blues’ rearguard boast the joint-third best in the division alongside Barnsley and Bristol Rovers.
Only Sunderland (13) and Blackpool (12) have picked the ball out of the back of the net on fewer occasions than Pompey.
Naylor, who returns from suspension for the trip to Bradford on Saturday, knows the Blues have been solid at the back this campaign.
But after score draws against Burton and Accrington, the midfielder believes it's crucial Jackett’s men get back to recording shutouts.
He feels if Pompey’s defence fails to be breached then they have the attacking prowess to punish teams.
‘Obviously our record is good but we want it to be first,’ Naylor said.
‘We’ve got to try to get back up there because I think getting clean sheets is where the points are at.
‘If we get clean sheets, we know we're going to score and get three points.
‘It’s always frustrating when you concede but it’s about how you respond.
‘When that’s happened, I think we’ve responded quite well.
‘Against Burton when we went 2-1 down we scored quite quickly.
‘Our response is quite good but noughts and ones is where we want to be at.
‘Our defensive record is good but we want it to be number one and continue to be at the top of the league as well.’