Mikkel Andersen is confident Pompey will turn around their fortunes this season.
The keeper waved goodbye to the Blues on Tuesday after his loan stint at Fratton Park came to a close.
Andersen has now returned to Reading as part of the terms of his 93-day emergency loan.
The 23-year-old was disappointed that the last game of his stay should be their seventh defeat on the bounce against Leyton Orient.
But he was adamant the Blues will turn around their fortunes.
Andersen said: ‘This is Portsmouth, this is a really big club.
‘You see that when you come here on a match day.
‘You see the quality that is there.
‘A club like Portsmouth will always bounce back. That’s the reason I came here.
‘It’s League One, but this is a big club and it’s been a good experience.’
Andersen insists he is now returning to Reading to vie for first-team minutes.
He said: ‘I have to get it in my head that I’m going back to Reading now to challenge to be number one.
‘I’m not going back to be another number, I’m going back to convince the manager I can play for him.
‘I have to be focused on this weekend now.
‘I’m like that. I wasn’t thinking about Reading before Leyton Orient, now that’s what I’m focused on.
‘I want to get some game time.’