Kenny Jackett was full of praise for Pompey's performance as they clinched a 2-1 triumph at Scunthorpe.
Tom Naylor and Gareth Evans netted in the first half as the Blues went four points clear at the top of League One, securing a maiden success at Glanford Park in the process.
Pompey were up against it in the final 20 minutes after Lee Novak got one back for Scunthorpe, but Jackett's troops saw it out.
And the Blues boss hailed his side's attacking and defensive efforts in the triumph.
He said: 'It was a really good performance I felt, against a good team.
'We grew in confidence on the ball and then towards the end, when we needed to, we really battled under a lot of pressure.
'We got our noses over the line negating them to very few, if any, chances at all.
'We did well against a side as physically big as Scunthorpe, especially with the amount of free-kicks they had today.
'We had balls put in to our box but we defended very well in that latter period.
'I was always looking for the thrid goal, whether that be in the first half or the early period of the second - where we continued to get in to some very good positions.
'We just couldn't quite get the finish, which would have given us some breathing space.
'It didn't come.
'You know the home side are going to put some pressure on you if you can't counter and get that third goal.
'As a barrage of balls came in to our box and a high number of free-kicks, we defended very, very well.
'We showed the other side of the game, which you do need if you are going to be a good team.'