Pompey have been warned they will be seen as a scalp for their League One rivals as they go to Colchester.
And Michael Appleton has told his players they have to be aware of a lull after the intensity of their campaign-opener against Bournemouth on Saturday.
A bear-pit atmosphere was created at Fratton Park against the Cherries, as fans roared their team on after a summer of doubt.
Appleton knows his men have to now lift themselves 72 hours later – against a team gunning to get one over them.
Pompey will be boosted, though, by bringing Jordan Obita in on loan from Reading, while international clearance is expected to be given to allow Liam Walker to feature.
Appleton said: ‘There was the emotion of the place on Saturday. The fans were amazing. I felt drained after the game, so the players will have felt the same. Now we go to Colchester as one of the big two or three sides in the division.
‘They will really want to do a turn on us, so we have to be guarded against that.’
– JORDAN CROSS