Mark Catlin has appealed for calm ahead of the south-coast derby.
Pompey host Southampton on Tuesday evening for the first time since December 2011, when the clubs shared a 1-1 draw in the Championship.
On this occasion, their fierce local rivals embark on the short trip to Fratton Park in the name of the Carabao Cup.
Inevitably a sell-out, it represents a welcome opportunity for the Blues to put aside their worrying League One form.
And Pompey’s chief executive has called upon fans from both sides of the M27 to make it a trouble-free encounter.
Catlin said: ‘We are urging fans to be passionate and get behind their teams on Tuesday night.
‘But we’re also keen to stress we want each and every fan that attends the game to go home safely and not do anything which could jeopardise their future, whether personally or professionally.
‘All too often in my time at Pompey, I have found myself sat in front of good fans that have made a stupid spur-of-the-moment decision which has then affected the rest of their lives.
‘I’m sure I don’t have to point it out that criminal records and banning orders can affect the employment opportunities of people.
‘Unfortunately, I have been party to conversations where people have lost their jobs – and it has also affected their future employment opportunities.
‘Ultimately, it's a passionate sport, nobody enjoys the highs and suffers the lows as much as I do, but it’s a game of football and we don’t want people to be hurt in any way, shape or form, whether that be physically or professionally.’
Catlin has been associated with Pompey since the 2012-13 campaign, yet this signifies his first south-coast derby experience.
And the West Ham supporter has been well prepped on what to expect.
He added: ‘I have attended Millwall v West Ham derbies and know how bad it can be. People I know and trust at Pompey tell me this is as bad, if not worse.
‘We want people to come, we want people to get behind their team, but we also want them to go home safely and without any long-term damage done to anyone.’