Newport County will need to overcome higher-ranked opposition for the second round in a row in order to progress in the Carabao Cup.
County twice came from behind to knock out Championship side Luton in round one, with Lewis Collins, Chanka Zimba and James Waite all finding the net in the Kenilworth Road upset.
Portsmouth were also victorious over second-tier opponents in round one though, as they thrashed Cardiff City 3-0 in the capital.
Newport will be hoping Saturday's 2-1 win over Tranmere will now kickstart the season for the Exiles while Pompey are 3rd in League One currently following the weekend's 3-1 win over Bristol Rovers.
Colby Bishop could be the man to watch for Danny Cowley's side, as he has five in six in all competitions, as well as an assist, so far while Connor Ogilvie has as many as County's top scorer Omar Bogle - three.
County will still be without Offrande Zanzala due to his tendon injury but hope to have Robbie Willmott and Aaron Wildig back in the first-team picture.
Portsmouth will not have Louis Thompson available who suffered a serious fibula injury at the weekend.
Victory tonight will see County progress to round three of the EFL Cup for the first time since 2020.