The Blues are out to make it 27 League One games unbeaten, but face an opponent who’ve won 10 of their last 11 visits to Fratton Park.
It appears something has to give with John Mousinho having injury and selection issues to contend with going into the game.
This is how we think he’ll go as he welcomes former Pompey boss Michael Appleton’s side to PO4.
5. LB: Jack Sparkes
The path remains clear for the assist king with Connor Ogilvie sidelined, but his form has been so good there's every chance he'd be starting anyway. Photo: Jason Brown
6. CM: Joe Morrell
Form has been so good and a pillar of consistency. Will have to relinquish the armband when Marlon Pack returns, but the leadership role remains. Photo: Jason Brown
7. CM: Alex Robertson
A wealth of possibilities here. Marlon Pack is set to be available for selection and could come back in, alternatively Ben Stevenson could start freeing Robertson to play further forward. We're plumping for the impressive Aussie continuing alongside Morrell, however. Photo: Jason Brown
8. RW: Paddy Lane
Continued his impressive form this season early on in the FA Cup last weekend, before fading with the rest of his team mates. Has to be seen as the winger who's impressed most so far this season. Photo: Jason Brown