And he insists further Fratton Park arrivals remain on their radar.
Pompey’s frustratingly slow start to the summer transfer window not only irritated supporters but boss Danny Cowley himself.
However, a flurry of new faces captured since midway through last month has rocketed their tally to nine.
The head coach subsequently handed seven debuts in Saturday's encouraging 3-3 draw at Sheffield Wednesday, with new-boy Colby Bishop among the goals.
Suddenly Cowley’s playing squad has been transformed – and Cullen is adamant the club’s approach was the correct one.
Pompey’s chief executive told The News: ‘I think our patience paid off.
‘We didn’t jump into anything knee jerk and held on for the players we targeted very early on in the calendar year, so the getting the likes of Colby Bishop into the building has paid off.
‘We still know we have some improvements to make and are working hard at that as we speak.
‘There’s obviously a lot of noise around football and people who will become anxious when they don’t see some of the key positions being filled, I quite understand that.
‘But the easiest thing is lazy recruitment, maybe going for anything that’s available at any particular time just to fill a hole or void.
‘Then you start to have issues such as what it means in terms of complementing partnerships, particularly in the forward position which, let’s face it, is always one of the more challenging areas of the field.
‘We are pleased we got to the stage where some of the patience did pay off. Take Dane Scarlett.
‘Like a lot of Premier League clubs, Tottenham want to take a really good look at a potential loan, making sure there’s a strong proper development plan for their young talent going out.
‘So they took a very, very considered approach - and we are very grateful to Spurs for entrusting us with the development of a really precocious young talent.’
The hunt continues to strengthen Pompey’s wing options ahead of the September 1 deadline.
As ever, Cullen is relaxed about the situation.
He added: ‘There are probably about a couple more players we’d like to bring into specific positions.
‘As Danny said, we’re particularly looking at those wide areas and a bit of pace coming into the side to build on what we have already achieved.
‘We’ve covered the goalkeeper, centre-backs, full-backs, while we feel the central midfield is well-stocked.
‘We’ve also now got three forwards in the building, which was really, really important to us and had obviously been challenging, but we wanted to play the patient long-game on that one.
‘The window still has 30 days to go, so we’re not even two-thirds through the transfer window yet.’
A message from the Editor, Mark Waldron
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