Pompey travel to Peterborough tomorrow with the stakes high in the League One promotion showdown.
Mousinho has fitness and injury issues to contend with, as he's tasked with blunting the division's more potent attacking force.
And then there is the big talking point of who starts up front out of Kusini Yengi and Colby Bishop?
What does Mousinho do in terms of formation, too, after switching to a back three against Burton on Tuesday night?
Here's how we think the Pompey boss will go against Darren Ferguson's side.
5. CB Conor Shaughnessy
Going to need all his mobility and quality on the ball this weekend. | National World
6. LB Jack Sparkes
Massive afternoon for left-back, with Sparkes expected to be fit after impact injury - and it's a huge test against Poku. Likely to be significant to game's outcome. | National World
7. CM Marlon Pack
More of the same is needed from Pompey's captain marvel. | Jason Brown/ProSportsImages
8. CM Owen Moxon
Real mixed bag from the new boy as he adjusts to new environment - but is now showing more of the quality he was brought in to produce. | National World