Pompey will look to record a fourth successive league win without conceding a goal when they host Wycombe on Saturday (3pm kick-off).
That has not been achieved since the Blues were in the Championship under Steve Cotterill – more than five years ago.
Standing in their way is a Wycombe side who have made a slow start to the 2016/17 campaign.
Gareth Ainsworth’s injury-hit outfit have won just once in League Two so far – a 2-1 home victory over Grimsby last month.
There have also been draws with Accrington and Blackpool, as well as defeats to Crawley, Colchester and Luton.
The latter was a 4-1 thrashing last Saturday and left the Chairboys down in 22nd spot – just one point above the drop zone at this early stage.
Wanderers looked like securing a play-off spot at last term, with even automatic promotion not out of reach at the start of April.
But they failed to win any of their last eight games and eventually had to settle for a mid-table berth.
That run included a 2-1 defeat at Fratton Park – with Gary Roberts and Conor Chaplin on target for the hosts – and Wycombe have yet to beat Pompey in any of their six previous league meetings.
Brandon Haunstrup (collarbone), Drew Talbot (hamstring) and Jack Whatmough (knee) are all still out for Pompey.
Adam Buxton (ankle) is back in training, but Saturday’s game will likely come too soon for the right-back.
New loan signing Dominic Hyam could make his debut after returning from international duty with Scotland under-21s.
The visitors have plenty of injury problems, with goalkeeper Scott Brown, defenders Joe Jacobson and Max Muller, midfielders Marcus Bean and Luke O’Nien, and forwards Paris Cowan-Hall and Myles Weston all expected to miss out.
Read what Paul Cook and Milan Lalkovic have to say about the game or watch pre-match video content on Pompey PlayerHD.
HEAD TO HEAD
Pompey: 2 Wins
Wycombe: 1 Win
At Fratton Park
Pompey: 1 Win
Wycombe: 1 Win
Tickets can be bought online here. They will be available to buy from the booths behind the Fratton End from 11am on Saturday.
Pompey PlayerHD subscribers can listen to live commentary from Fratton Park from 2pm on Saturday.