Pompey will definitely be top of the League One table at Christmas after securing a 1-1 draw against fellow promotion hopefuls Barnsley at Oakwell.
But they might have been celebrating an even greater haul, as Gareth Evans drilled them into the lead just before the break.
Amidst a freezing downpour, however, Cauley Woodrow levelled in the second half and the Blues were forced to hold on at the end.
A stalemate was probably not the biggest surprise, with the hosts boasting an unbeaten home league record and the visitors having not been beaten on the road.
Kenny Jackett stuck with the same side that were beaten by Charlton on home soil earlier in the week.
But with Luke McGee suffering from a hand injury, Alex Bass was recalled from a loan spell at Torquay to sit on the bench.
It was not exactly the right day for a neat, passing game of football, with freezing rain falling from the South Yorkshire sky throughout.
That did not seem to dampen the entertainment on offer, however, as the game was often played at a frantic pace.
It was the hosts who looked on top for much of the first half, although they were let down by some poor finishing.
Pompey actually had the first opening, but Ronan Curtis took a heavy touch from Jamal Lowe’s threaded pass, allowing Adam Davies to come from his line and claim.
Craig MacGillivray was the busier of the two keepers, however, and he had his palms stung by Woodrow.
Meanwhile, some vital tracking back from Evans and Lowe denied Cameron McGeehan and George Moncur respectively.
MacGillivray was called into action again midway through the first half, palming over a fierce drive from Woodrow.
The keeper also kept out an angled Moncur shot, while an effort from McGeehan was then diverted off target.
There was a brief interruption soon after, as one of the floodlights failed, but after consulting with both managers, referee Jon Moss decided it was fine to continue.
Pompey threatened on 33 minutes when Lee Brown whipped in a dangerous cross that Lowe volleyed wide.
Kieffer Moore fired wastefully wide at the other end, while some more good defending from Lowe stopped Brad Potts’ surge.
It was Barnsley on top as the interval approached, but the Blues were able to break the deadlock on 43 minutes.
Alex Mowatt tried to clear the ball, only to send it straight into the path of EVANS, who hit a crisp left-footed shot into the bottom corner from the edge of the box.
Half Time: Barnsley 0 Pompey 1
Both sides were struggling to keep hold of possession once the action restarted, no doubt hindered by the wet and windy conditions.
Long-range efforts from Jacob Brown and Potts went over the bar, as Barnsley went in search of a leveller.
The home crowd were growing frustrated and were appealing to Moss for some soft penalties, with each turned down by the official.
But their mood improved just after the hour mark, as Potts sent in a low cross that Woodrow neatly turned home at the near post.
Barnsley moved up a few gears after that, only for the Blues to then create an opening on the counter-attack.
Ben Thompson collected the ball in the centre and fed Oli Hawkins, whose low drive was kept out by the boot of Davies.
Curtis thought he should have been awarded a penalty after going down in the box, but Moss thought he fell too easily and brandished a yellow card.
The Republic of Ireland international was withdrawn moments later, with Anton Walkes coming on and Nathan Thompson joining Matt Clarke and Jack Whatmough in a back three.
It was still the Tykes looking more of a threat as the game entered its closing stages and Tom Naylor bravely threw himself in front of a thunderous Woodrow effort.
And they almost snatched a late winner, with Moore collecting a pass from Lloyd Isgrove, turning and sending a low shot inches past the post.
Barnsley (4-4-2): Davies (c); Cavare (Brown 46), Jackson, Pinnock, Pinillos; Potts (Thiam 80), Mowatt, McGeehan, Moncur (Isgrove 63); Moore, Woodrow
Goals: Woodrow 61
Booked: McGeehan, Woodrow
Subs not used: Greatorex, Lindsay, Bahre, Adeboyejo
Pompey (4-2-3-1): MacGillivray; N.Thompson, Whatmough, Clarke, Brown; Naylor, B.Thompson; Lowe, Evans (c), Curtis (Walkes 75); Hawkins
Goals: Evans 43
Booked: Naylor, Curtis, Brown
Subs not used: Bass, Burgess, Close, Donohue, Green, Pitman
Referee: Jon Moss
Attendance: 12,441 (1,674 Pompey fans)