The Magpies hopes of springing a cup shock were dashed as League One table-toppers Blues, the highest-ranked team in the competition, ran out comfortable winners.
Efforts from Ben Thompson, Oli Hawkins, Jamal Lowe and substitute David Wheeler proved the difference, with National League strugglers Maidenhead suffering another defeat.
Following the loss, former England international Devonshire feels now is the time to act and make some changes at the club.
And he did wish Pompey well in their quest to reach the Championship after the FA Cup defeat.
Devonshire told BT Sport: '˜I was quite pleased with the first half.
'If we could have held on, not conceded a couple of minutes before the break, you never know.
'I think when the second goal went in we gave up a little bit.
'We're very brittle at the moment.
'I've told the players I think it's time we need to move a few out and get a few new faces in.
'We're not that hard to beat really, I know they're a good side, but from my point of view we need to roll our sleeves up and have a go '“ at least more then we're doing at the moment.
'We're not taking responsibility at the moment.
'But this was a game I was hoping we could learn from - we have - I'm just disappointed in the way we lost it.
'But good luck to Portsmouth. I hope they go up because they're a big club.'