Kenny Jackett hailed Pompey’s defensive performance after the Blues kicked off their League One campaign with victory.
Yet the dogged hosts were made to cling on to secure that 1-0 result, as the visitors applied constant pressure, striking both the post and the bar.
With Matt Clarke and Jack Whatmough superb in defence, it was a magnificent rearguard action.
And Jackett was delighted with his team’s resilience.
He said: ‘I thought we defended very well – we needed to.
‘We showed fantastic commitment and desire to make sure we earned something. They are qualities you need throughout the season and they were there,
‘We showed great spirit, great heart, great determination and defended very, very well.
‘In terms of ball retention, we didn’t do enough and I thought it resulted in Luton, after the first 20 minutes, going wave after wave after us and our first pass out of defence and general ball retention wasn’t really there.
‘We didn't do enough in possession to create enough chances that we needed as the home side.
‘A lot of positives there in terms of heart, defending and commitment, which are qualities good sides possess – but we want to build on that, though.’