The Blues collected a goalless draw at Cambridge United and, in truth, deserved little more against a side humbled by Cheltenham in their last outing.
Having been rescued in stoppage time on Saturday by a central defender, they were not going to be fortunate once more 72 hours later.
John Mousinho’s men dominated possession and reached double figures in terms of goal attempts, yet, tellingly mustered just two on target for the entire match.
Indeed, it was goalkeeper Will Norris they had to thank for even securing a point when, in the second half, he produced an excellent point-blank stop from Jack Lankester.
Mousinho had sprung a selection surprise by changing his full-backs, opting to rotate his squad, with Joe Rafferty and the in-form Jack Sparkes making way – to be replaced by Zak Swanson and Connor Ogilvie.
Yet an early injury to Ogilvie brought Sparkes back into the side and not even his dead-ball quality could not unlock a victory for the Blues this time around.
The draw meant it brought to an end seven successive wins for Mousinho – but it remains a point to appreciate considering results elsewhere.
Oxford United’s defeat at Wigan means the League One leaders extend the gap at the top of the table to four points with their Abbey Stadium result.
And while the noisy 1,470 travelling faithful didn’t savour victory on this occasion, it represents another step towards that cherished Championship return.
Mousinho made three alterations to the team which left it so late to defeat Carlisle on Saturday, with the omissions of Rafferty and Sparkes leading the way.
Completing the changes was Tino Anjorin making way for Christian Saydee following his second league outing for the Blues at the weekend.
Sean Raggett missed out on the 18-man squad through illness, so Ryley Towler took his place on the bench.
Yet there was no Gavin Whyte or Terry Devlin among the substitutes, while Marlon Pack, Tom Lowery and Anthony Scully remain in the treatment room.
Before kick-off, there was a minute’s applause in honour of the late Bobby Charlton, who passed away on Saturday at the age of 86, with both sets of fans touchingly chanting his name.
When the match got underway, the Blues were forced into a change on eight minutes when the returning Ogilvie limped off with an apparent ankle issue.
He was replaced by Sparkes at left-back, with the former Gillingham man understandably gutted to be departing so early into his comeback.
Moments later, Sullay Kaikai caused problems down the left and his cross was clawed out for a corner by Will Norris from dangerously under his crossbar.
At the other end, Paddy Lane dispossessed centre-half Ryan Bennett on the edge of the box to put himself clean through, yet lost his footing and, in the process, surrendered possession.
The game burst into life on 31 minutes when Abu Kamara’s cross from the left took a slight deflection off Liam Bennett and struck the inside of the far post.
Colby Bishop followed up, presented with an open goal, yet as he shot, Ryan Bennett threw himself in front to block the attempt and save the day for the U’s.
Moments later, Swanson had a glimpse of goal from outside the box, yet his right-footed drive would embarrassingly strike the roof on the stand behind the goal.
Pompey were dominating possession, yet not carving out too many chances, although, with half-time approaching, a penalty-box melee resulted in Shaughnessy’s shot being deflected over.
There were no substitutions at the break for either side, with Pompey now attacking the end holding their travelling supporters.
The Blues began strongly, camped in the hosts’ half and, on 50 minutes, Swanson capitalised on a slip inside the box by a Cambridge player, only to shoot straight at the keeper.
Pompey were forced into another substitution through injury on 58 minutes, with Saydee replaced by Anjorin, having twice gone down for treatment within a few minutes.
Despite their dominance, the Blues required some inspiration to break the deadlock and on 62 minutes Lane cut inside from the right and fired a left-footed attempt just over the bar.
The game boiled over on 67 minutes when Kamara caught keeper Jack Stevens when attempting to intercept a backpass and, in the aftermath, Morrell sprinted forward and pushed over Morrison.
Both Pompey players earned bookings for their actions, rightly so, although inevitably the home fans were calling for a red card.
Those incidents appeared to ramp up the atmosphere and the home fans were encouraged when Norris pulled off a brilliant instinctive save from Lankester on 73 minutes.
The match was starting to peter out, with a goalless draw looking ever more likely with neither side capable of digging out the quality to settle the encounter in their favour.
If anything, it was the U’s finishing the more dangerous side, with some searching moments for the well-drilled Blues backline to deal with.
Yengi came on for Kamara in the 90th minute to try to find a breakthrough and there were some tense moments for the hosts from Pompey corners.
However, there was no way through and the match ended with Robertson slicing a shot well wide of the target, much to his obvious frustration.
Frustration also for Pompey, having failed to meet their own high standards this season, yet didn’t produce enough quality and creativity to claim they warranted anything more from this fixture.
That’s now 25 matches unbeaten and a four-point lead at League One’s summit – still plenty to appreciate, despite serving up a disappointing draw.