Simon Eastwood waved goodbye to Pompey and admitted: I owe you so much.
The keeper has spoken of his debt to the Blues following the completion of his move to Blackburn.
Eastwood revealed it was a difficult decision returning north after making a switch to Fratton Park from non-league football last summer.
The 23-year-old explained being close to his family, with his partner expecting their first child, was a key factor in turning down the offer to stay at Pompey in favour of Ewood Park.
Eastwood has been inundated with good-luck messages from Blues fans on social network sites.
He thanked the Fratton faithful for their backing and also spoke of his appreciation towards manager Guy Whittingham for giving him his chance with Pompey.
Eastwood said: ‘I’ve loved my time at Portsmouth.
‘The response I’ve had from Pompey supporters sums the club up a whole, really.
‘I feel Portsmouth gave me a chance so they will always be close to me.
‘I’ll definitely be looking out for them and keeping in touch with the lads.
‘It was a really tough call.
‘I’ve got my family from up north and I’m a northern lad.
‘A lot of it is location, with a baby on the way. That was a big part of it.
‘I’d like to think most people would do the same with the family situation I’m in.
‘But I owe Portsmouth so much and I have to thank them and Guy, especially, for giving me a chance.
‘Portsmouth is a great club. The lads and the fans, especially, make it that.
‘I think Guy will do well next season. I definitely think he’s the right man for the job.
‘The coaching staff know their stuff. I can’t speak highly enough of them.
‘I definitely think they can bounce back next season and I’m definitely rooting for them.
‘I’ll be looking out for them every week. I’m sure they’ll come straight back up.’
Eastwood went on to make 30 Pompey appearances after breaking into the starting line-up over the second half of the season.
After a miserable period of 23 games without a win, he played a key role in the Blues’ run of a single defeat in nine games – with four clean sheets arriving in seven outings.
Eastwood believes he can go to Blackburn and establish himself like he did with Pompey.
He said: ‘I have to do at Blackburn what I did at Portsmouth. No-one really expected anything of me but I got my head down, worked hard and then I broke through.
‘I played 30 games in the end. Once I get into the team I’m confident in my ability to stay there. With Blackburn being a Championship club and, possibly, a Premier League club, it was really hard to turn down.
‘I think you have to be confident in your own ability, especially as a keeper. I’m backing myself to go to Blackburn and make an impression.’