Pompey will look to recover from just their fourth league loss of the season when they visit Oxford on Saturday.
They still enjoy a four-point lead at League One summit, with nearest rivals Luton and Sunderland sharing the points last weekend.
The Blues’ next opponents are also desperate to accumulate points – although for a very different reason.
Karl Robinson’s men are currently sitting inside the drop zone, but are only a single point behind the safety line.
United have failed to win any of their past five league fixtures – a run that included three successive defeats before a 2-2 draw at Fleetwood in their most recent outing.
Their FA Cup and Carabao Cup campaigns both ended at the third round, going out to Brentford and Manchester City respectively.
But Oxford have – like Pompey – reached the quarter-finals of the Checkatrade Trophy, seeing off Cheltenham on penalties to set up next week’s clash with Bury.
The Blues eased to a 4-1 victory when the sides met on the south coast back in August, despite Gareth Evans having a penalty saved.
He redeemed himself by netting after the break, however, and Jamal Lowe added a brace, while Rob Dickie found his own net.
Lee Brown and Ben Close are both back in contention for Pompey, while Bryn Morris could make his debut after signing from Shrewsbury.
But Andre Green has been recalled from his loan spell by Aston Villa and the Blues are still missing Oli Hawkins (calf), Luke McGee (wrist) and Nathan Thompson (hamstring).
Shandon Baptiste, Rob Hall and Jon Obika all have long-term injuries for the hosts, with former Pompey winger Ricky Holmes (back) also out and Jamie Hanson (ankle) a doubt.
HEAD TO HEAD
Pompey: 25 wins
Oxford: 21 wins
Pompey: 8 wins
Oxford: 17 wins
Pompey have sold their full allocation of tickets and no more will be available to buy on the day of the game.
Fans travelling to the game can click here for a guide to the stadium.
Overseas subscribers and match pass holders can watch the action – now with on-screen graphics – and commentary will begin from around 10 minutes before kick-off.
ALSO IN LEAGUE ONE
AFC Wimbledon v Barnsley
Blackpool v Shrewsbury
Bradford v Southend
Bristol Rovers v Wycombe
Charlton v Accrington
Doncaster v Burton
Gillingham v Walsall
Luton v Peterborough
Plymouth v Coventry
Rochdale v Fleetwood
Scunthorpe v Sunderland