Pompey travel to Luton Town on Saturday in the first round of the FA Cup and hold the recent bragging rights over their opponents.
The Blues go into the tie unbeaten in their past seven meetings against the Hatters.
More impressively, Pompey have won five of those matches and drawn two.
You have to go back over 22 years to September 30, 1995, since the Blues were defeated by Luton.
Terry Fenwick’s side suffered a 3-1 loss at Kenilworth Road, with Paul Walsh on target for the visitors.
However, Pompey reversed the result that season with a 4-0 romp at Fratton Park.
Paul Hall scored a double, with Walsh and Jimmy Carter also on target.
Last term, Paul Cook’s side did the double over Nathan Jones’ outfit on the way to the League Two title.
They earned a 3-1 victory against the Hatters at Kenilworth Road, with Michael Smith, Gareth Evans and Kal Naismith all netting.
The clash at Fratton Park was a tighter affair, but Christian Burgess’ 31st-minute header proved the difference and sealed the three points for the Blues.
Gary Roberts also blazed a second-half penalty over the bar.
Pompey were also victorious at Kenilworth Road during the 2015-16 season when Matt Tubbs’ last-minute strike ensured the visitors returned to Fratton Park with a 2-1 win.
However, the Blues cannot brag about their overall record against Luton – and certainly not their past clashes in the FA Cup.
From 50 meetings between the two sides that date back to the 1920-21 campaign, Pompey have won 16 matches, drawn 13 and lost 21.
In the world’s oldest cup competition, it’s the Hatters who have the edge, winning three and drawing one of their match-ups with the Blues.