David Forde has urged patience as Pompey strive to recover from their poor start.
The Blues recorded a late win over Colchester on Saturday – marking their first victory of the campaign.
We are focussed on getting promoted so get right behind us now because if they do we can be more than a force to be reckoned with this yearDavid Forde
The previous three league matches had yielded two points, prompting rising criticism among some fans.
Paul Cook’s side now find themselves in 14th, with Forde establishing himself as a calming presence in the defence.
The veteran keeper pulled off several late stops against Colchester to ensure the points arrived at Fratton Park.
And he believes expectations should not get out of hand.
He said: ‘Saturday was a huge win, especially for a club like Portsmouth who are expecting to be top of the league and probably rightly so.
‘It’s important we manage those expectations because if we don’t do it correctly it can lead to disappointment.
‘It’s also important the fans remain patient and the players remain patient because I feel we are doing the right things and have the squad to be successful – it is about encouraging the players.
‘Expectations are something you have to acknowledge being at a club like this.
‘You see the crowds and the size of the club, it’s difficult looking at past glories and the FA Cup and the Premier League followed by all the troubles,
‘I suppose there is a lot of frustration from the fans over the way things have been going but it is important they understand this is a new team and that’s in the past.
‘We are focused on getting promoted so get right behind us now because if they do we can be more than a force to be reckoned with this year.
‘Football is about patience and tolerance, and not having that kills clubs as well.
‘It is important we remain patient and I think we will really get it right and hopefully go on a good run.’
Forde’s arrival has solved Cook’s long-standing goalkeeping problem.
Arriving on the eve of the season, he featured in only one pre-season friendly – a goalless draw at Bristol City.
He has subsequently kept two clean sheets in his first four Blues appearances.
And the ex-Millwall keeper believes he has settled in well.
He added: ‘The lads have been fantastic, the staff great and the fans so supportive, I am thoroughly enjoying my time.
‘We have been the best side in all the games, creating chance after chance after chance, although were unfortunate against Carlisle and the Morecambe keeper.
‘We knew that couldn’t keep happening and the ball would soon hit the back of the net.
‘Thankfully we won on Saturday.
‘It is important we keep doing the right things, which I feel we are. It’s about keeping the right shape and being disciplined as well.’