Pompey can book their place in the knockout stages of the Checkatrade Trophy at Charlton this evening.
Victory would see them secure top spot in Southern Group A, while two points (a draw with a penalty shoot-out bonus) would be enough to nail down second place.
However, should the Blues leave The Valley with one point or fewer, they face a long wait to see whether they will compete in the last 32.
In that instance they could still be caught by Fulham’s under-21 side, but they do not play their final group match at already-eliminated Crawley for another three weeks.
Charlton have already sealed their progress and are looking to record a fifth successive win in all competitions.
That run includes Saturday’s Emirates FA Cup defeat of non-league Truro and a Checkatrade Trophy comeback against Fulham, which saw them trailing 2-1 entering the 89th minute.
Karl Robinson’s men are currently sitting fourth in the League One standings and are six points adrift of the automatic promotion places, albeit with a game in hand.
The last meetings between the sides took place in the Premier League during the 2006/07 campaign.
Both won 1-0 on their opponents’ patch, with Lomana LuaLua’s strike sealing victory for Pompey at The Valley.
Damien McCrory (knee) and Jack Whatmough (knee) are still sidelined, but Pompey otherwise have a full-strength squad to choose from.
Stuart O’Keefe and Nathan Thompson can both feature, as their one-match bans do not include games in the Checkatrade Trophy.
Charlton are expected to make plenty of changes for the game, with former Blues winger Ricky Holmes unlikely to appear.
HEAD TO HEAD
Pompey: 41 wins
Charlton: 33 wins
Pompey: 15 wins
Charlton: 19 wins
Seats can be secured from the West Stand ticket office (cash only) at The Valley this evening. Click here for a list of prices.
Please note that there is no live video coverage for overseas subscribers, but they can also listen to audio by following the same instructions.
Charlton are 13/10 favourites with Sky Bet to secure all three points, while the Blues can be backed at 2/1.
Click here to read our full betting guide and visit www.skybet.com/pompey for great offers and promotions. Please gamble responsibily.
ALSO IN CHECKATRADE TROPHY
Bradford v Rotherham (7.30pm)
Newport v Cheltenham (7.30pm)
Oldham v Newcastle U21 (7.30pm)
Cambridge v Peterborough
Coventry v West Brom U21
Gillingham v Reading U21
Lincoln v Notts County
Morecambe v Leicester U21
Northampton v Southampton U21
Oxford v MK Dons
Port Vale v Crewe
Rochdale v Blackburn
Shrewsbury v Walsall
Southend v Colchester
Stevenage v Brighton U21
Wigan v Accrington
Bristol Rovers v Swindon
Bury v Stoke U21
Carlisle v Fleetwood
Grimsby v Sunderland U21
LAST TIME OUT IN CHECKATRADE TROPHY