Mark Catlin has appealed for unity as Pompey seek to propel themselves away from relegation danger.
A very small number of Blues fans present turned on boss Richie Barker during Saturday’s 3-1 defeat at Fleetwood.
There were several chants of ‘Barker Out’, while around four Pompey followers in corporate hospitality voiced their opinion during the manager’s post-match interviews.
It was only a third defeat in the past 13 matches – a period which has seen the Blues placed among League Two’s in-form sides.
Nonetheless, Barker’s men remain entrenched in serious relegation trouble, with a number of their rivals playing tonight.
And the Highbury Stadium defeat represented the first occasion fans had reacted in such a manner towards their manager.
Chief executive Mark Catlin said: ‘While everyone is clearly frustrated at the moment, the focus is on quickly turning it around.
‘We must be united and we need the fans as the 12th man they are so renowned for.
‘I can understand the frustration with our position, but we are where we are.
‘The best way of getting out of it is sticking together and getting behind the side, especially when things are not going well.
‘I heard the chant myself on Saturday. There were not that many taking part in it and, from what I heard, it was quickly drowned out by ‘Play Up Pompey’.
‘A vast majority of the fans didn’t think that was constructive.
‘If you have two or three people in corporate, there is nothing you can do about that. People hurt and want to voice their frustrations.
‘The best way at this moment is to support the team and get behind them.
‘There are nine big games ahead. It is going to be up and down, so we must stick together.’
The Fleetwood defeat means Pompey are now four points above the relegation zone.
Current incumbents in the bottom two – Northampton and Torquay – each have a game in hand and are in action tonight.
The Cobblers host third-placed Rochdale on the back of improved form of 16 points from their past 10 matches.
As for Torquay, they host Bury, who are in 17th spot –level on points with Pompey.
Elsewhere at the bottom of the table, Accrington host Morecambe, while Wycombe visit Cheltenham.
In the meantime, Barker has a crucial home match with York on Saturday to prepare for. And Catlin doesn’t believe recent criticism will knock Pompey’s boss out of his stride.
He added: ‘I haven’t spoken to Richie about what happened, but he’ll just get on with it.
‘Managers get it at all clubs up and down the country, people sometimes have a go.’