Doncaster Rovers provide the obstacle to equalling the best winning start to a league campaign in Pompey history.
Since Blues days of the Southern League Division One in 1899, on just one occasion has a conventional league season kicked off with five successive victories.
That arrived in 1979-80 under the guidance of Frank Burrows.
Now Kenny Jackett’s side have the opportunity to match that feat – providing they can secure a triumph at the Keepmoat Stadium on Saturday.
So far Luton, Blackpool, Oxford United and Bristol Rovers have been defeated during the opening four league fixtures of the current campaign.
In doing so, Pompey have matched a four-game league streak last established 38 years ago.
Also under Burrows, that arrived at the beginning of the 1980-81 season at Division Three level.
In terms of winning the opening five league matches to a season, that was established the previous year – in a Blues promotion campaign.
And it remains the first and only instance in Pompey’s 119-year competitive history, not including the South Hants War League from 1917-19.
Back in 1979-80, Burrows’ team included Alan Rogers and Steve Aizlewood among five league debutants during a Division Four opening-day 3-0 triumph over Hartlepool.
The side went on to see off Torquay, Scunthorpe, Wigan and Stockport in consecutive fixtures.
That winning run ended with a 4-1 loss at Tranmere, Pompey hampered by being reduced to 10 men following John McLaughlin’s dismissal.
Remarkably, that was their sole loss during the opening 11 league matches, claiming victories in the other 10 fixtures.
In fact, the 1979-80 campaign saw Burrows’ men win 12 and lose twice during the opening 14 league games, entrenching them in top spot by mid-October.
However, form then became sporadic, while leading scorer and fans’ favourite Colin Garwood was controversially sold to Aldershot in February 1980.
Ultimately, three successive victories at the season’s end, including a last-day 2-0 win at Northampton, earned promotion in fourth spot.
That was achieved by the narrowest of margins – goal difference ahead of Bradford.
Now Jackett’s men head to Doncaster seeking to create their own piece of Pompey history and emulate Burrows’ side.