Late goals deprived Pompey of five points in League One last season.
Kenny Jackett’s men have already surpassed that costly tally – after just 13 matches.
Craig MacGillivray’s unfortunate own goal registered on 90-plus-three minutes denied the Blues a well-deserved victory at Bristol Rovers on Saturday.
It also represents the sixth point relinquished in the final 10 minutes of League One action before the end of October.
With Jackett’s men already challenged with a lengthy pursuit to catch the promotion pacesetters, the staggering statistic does little to aid their chase.
Pompey are presently 16th – restoring those dropped six points would leave them positioned seventh.
A case of what could have been for a team which have carelessly let three points slip in stoppage-time during the past two away matches alone.
In addition to their Memorial Stadium heartbreak, they also conceded in the third minute of time added on at AFC Wimbledon the previous weekend.
Except, on that occasion, Terell Thomas’ header initiated defeat from the position of a goalless Kingsmeadow draw.
In fact, in each month of the 2019-20 campaign, the Blues have discarded points courtesy of late goals.
Most notably was August’s visit of Coventry, when Michael Rose’s 86th-minute leveller secured a 3-3 draw for the nine men.
Pompey had led 3-1 and 3-2 against Mark Robins’ side, who incurred two sending offs during a frantic Fratton Park second half.
In October, an awful footballing spectacle at Wycombe came to life on 83 minutes after Adebayo Akinfenwa hammered home a decisive penalty, the lost point leaving the Blues in 20th place.
Earlier this month, it also appeared Reece James’ 82nd-minute strike had deprived Jackett’s men of two points at Doncaster.
However, Ellis Harrison’s goal one minute into time added on snatched victory – representing two of three points this season netted in the Blues’ favour late on.
The other was Brett Pitman’s penalty on 90-plus-four minutes, which completed a comeback from 2-0 down against Burton last month.
In contrast, during 2018-19, Pompey dropped five points, with two against Wycombe (September 2018) and Southend (February 2019) – and a point lost at Luton (January 2019).