Pompey had to settle for a 2-2 draw after a spirited second-half showing from Burton at Fratton Park.
Kenny Jackett's side looked well in control of the League One encounter at half-time, with Oli Hawkins' third goal of the season handing them a well-deserved lead.
Yet the Brewers silenced Fratton Park within six second-half minutes when substitute Devante Cole and then Jake Hesketh handed the visitors a surprise advantage.
The shell-shocked Blues gathered their composure to draw level on 57 minutes thanks to Matt Clarke's header.
But they were unable to regain the lead in the 33 minutes remaining, instead settling for a draw when so much more looked on offer.
Pompey came out of the traps like a team on a mission, penning the Brewers into their own half.
Lee Brown fizzed in two crosses from the left that had visiting keeper Dimitar Evtimov on alert, while Dion Donohue - who came off midway through the first half with what looked a hamstring injury - had his inswinging corner clawed off the line by the increasingly busy stopper.
Ronan Curtis was next to register an attempt, with Evtimov pushing hisright-foot curler from the edge of the box round the post, before Ben Thompson tried his luck from long range, after Tom Naylor dispossesses Jamie Allen.
The Burton keeper was offered some respite as opposite number Craig MacGillivray rushed off his line to stop Allen in his tracks.
Meanwhile, Will Miller will have regretted his scuffed shot when he was slid through by Ben Fox.
That gave the visitors a foothold in the game they'd been craving, but it didn't last long as Jack Whatmough's attempted overhead kick on 33 minutes once again drew Evtimov into action.
Substitute Gareth Evans' could perhaps have done better with Pompey's next effort on goal when he headed over from Jamal Lowe's cross.
Yet it wasn't long before the Fratton faithful were celebrating, with Hawkins glancing home Thompson's flying cross on 36 minutes.
It was a goal the hosts deserved, and one they retained going into the break.
It appeared all too easy for the Blues in the first half - it was anything but in the second.
Within six minutes of the restart, they were 2-1 behind.
The alarm bells were ringing on 47 minutes when MacGillivray was forced into a save from Liam Boyce's effort from 25 yards - gathering at the second attempt under pressure from substitute Cole.
But less than a minute later, Cole had made his mark, tucking home Allen's cross from the left with the bemused Pompey defence helpless.
Much to the home fans' amazement, Burton then had the audacity to take the lead on 51 minutes.
Hesketh wriggled his way past several outstretched Blues legs to fire high into the net from an acute angle.
Pompey's response was immediate, with Evtimov denying Lowe from close range, before Evans saw his volley blocked on the line.
There was clearly no sign the Blues had been left concussed by Burton's bullldozing start to the second half.
And that was reinforced when Clarke drew Jackett's side level with a towering 57th-minute header from Evans' corner.
On 62 minutes, Evans was inches away from handing the Blues the lead again as he attempted to get on the end of Lowe's daisy-cutter across the six-yard box.
Brown tried his luck from a free-kick 25 yards out that was easily gathered by Evtimov.
Meanwhile, at the other end, Stephen Quinn's long-range effort took a deflection before being collected by a relieved McGillivray.
Despite both teams clearly fancying their chances of emerging victorious, the effort put into that enthralling start to the second half appeared to have taken a lot out of both, although Thompson remained at his industrious best.
Passions were raised by both players and fans when John Brayford wrestled Curtis to the ground on the 90-minute mark, with the Fratton faithful incensed that no card followed for the Burton defender.
Substitute Brett Pitman was appealing for a penalty in injury-time when his free-kick looked to strike the arm of a Brewers player.
And although, Pompey earned a corner from the resulting effort on goal, they had to settle for a share of the spoils on a frantic night at Fratton Park – a result that sees their lead at the top of the table reduced to four points.