Pompey will help Charlton celebrate 25 years back at The Valley when the clubs clash on Saturday.
But the thousands of Blues fans making the trip to the capital will hope it is their side who have reason to party come 5pm.
Kenny Jackett’s men have already triumphed once there this season, although there were certainly not as many supporters there for last month’s contest.
Just 206 away followers were present to watch Curtis Main seal a Checkatrade Trophy group stage victory.
It is League One points up for grabs this weekend, however, and the sides are closely matched in the current standings.
Charlton are two places – and six points – higher in sixth spot, although they do also have a game in hand.
But Karl Robinson’s troops have collected just one win from their past four league outings to dent their automatic promotion hopes.
Pompey have not visited the Addicks for a league fixture since both sides were in the top-flight during the 2006/07 campaign.
Lomana LuaLua’s strike was enough to secure all three points for the Blues, although Charlton triumphed in the return fixture at Fratton Park.
Brett Pitman is set to return to the Pompey side after returning to training following a hamstring injury.
But there are still doubts over the availability of Ben Close (thigh), Dion Donohue (back), Oliver Hawkins (hamstring) and Kal Naismith (knee).
Milan Lalkovic (Achilles), Damien McCrory (knee) and Jack Whatmough (knee) are all still sidelined for the Blues.
Former Pompey defender Jason Pearce could be fit for the hosts, but Patrick Bauer (foot) and Tariqe Fosu (hamstring) are both out.
HEAD TO HEAD
Pompey: 42 wins
Charlton: 33 wins
Pompey: 16 wins
Charlton: 19 wins
Pompey have sold their full allocation of tickets for Saturday’s match and no more will be made available. Please do not travel without a ticket.
Overseas subscribers can watch the match live by following the same instructions.
ALSO IN LEAGUE ONE
Blackpool v Rotherham
Bradford v Rochdale
Bristol Rovers v Southend
Bury v AFC Wimbledon
MK Dons v Shrewsbury
Oldham v Northampton
Oxford v Doncaster
Peterborough v Blackburn
Plymouth v Gillingham
Walsall v Scunthorpe
Wigan v Fleetwood