Paul Cook has warned about Pompey complacency for their clash with rock-bottom Dagenham & Redbridge.
John Still’s side are 11 points adrift of safety at the foot of League Two, with 23 defeats in 39 matches.
They warmed up for tomorrow’s visit of the Blues with a 2-1 victory over Morecambe in the week.
Cook was in the crowd for what represented the Daggers’ second home win this season, with Jamie Cureton and midfielder Joss Labadie netting.
In reality, the result appears too little to save a side which appears destined to leave the Football League.
Yet Cook remains wary of the threat the strugglers pose as they continue to fight for their lives.
And there will be no underestimation as Pompey seek the victory to maintain their promotion push.
‘You have got to realise Dagenham, as a team, as a club, have always had good home records,’ Cook said.
‘The majority of games they have lost this year have been by the odd goal, by a late goal.
‘I was there on Tuesday night and they don’t leave anything on the pitch.
‘Anyone who thinks you are going to go there and just walk over them, well that is not going to happen tomorrow.
‘They are fighting and scrapping for their lives, the honesty in the team shines through and certain lads such as Jamie Cureton can score goals no matter who they play against.
‘John Still knows the game inside out so it will be a tough day for us and we have got to make sure we turn up.
‘This is a very, very dangerous game.’
The Daggers won their first home game of the season only last month – a 1-0 victory over fellow strugglers York.
That was followed up with that victory over Morecambe to keep faint hope of avoiding the drop alive.
But Cook points to other Victoria Road games when the opposition have struggled.
He added: ‘Plymouth equalised in the 90th minute there earlier this season, Accrington recently scored seven minutes from time to win 1-0.
‘So anyone who thinks you just have to turn up is mistaken.
‘You look at Yeovil when we went there and scraped a point.
‘In their next two home games they drew 0-0 with Plymouth and beat Accrington 1-0.
‘There are no easy games, you don’t just turn up. You have to earn that right – and we must do that tomorrow.’