Pompey will face an FA Cup replay at the Recreation Ground after a late Danny Hollands header spared them the embarrassment of being knocked out of the competition by non-league opposition.
Andy Awford's men produced a terrible performance and can consider themselves fortunate to be in the hat for the second round draw tomorrow as Aldershot showed more desire to win the tie.
Nigel Atangana replaced James Dunne in an otherwise unchanged team and the latter was certainly missed as the Shots deserved to win the game and may well be disappointed to come away from Fratton Park with only a replay.
However, Pompey did start the match well and after former Blues keeper Phil Smith was forced into a couple of routine saves by Jed Wallace and Craig Westcarr, the hosts were awarded a penalty for a clumsy challenge by Glenn Wilson on the latter.
Wallace made no mistake from the spot to give Pompey the lead but complacency must have set in after that goal as the intensity levels dropped and Aldershot began to play themselves into the match.
Therefore it was no surprise when they equalised on the stroke of half time as Dan Holman took advantage of some very sloppy defending from the full back position and whipped in a cross at the far post for Jordan Roberts to ghost in and convert the equaliser.
Fans in the ground would have expected Awford to read the riot act to his players at half-time but instead it was the visitors who improved as Pompey played like a Sunday League team.
The Shots took control of the game and Awford's reaction was to bizarrely take off Westcarr and replace him with Ben Close as Pompey went to a 4-5-1 formation at home to Conference opposition.
That change proved to be disastrous as Close's error gifted Keiron Forbes possession on the flank and he fired a cross into the box which was turned in by Mark Molesley and the cup upset was on.
Ryan Taylor was sent on to try and find an equaliser but it never looked like coming with some terrible passes and stupid offside decisions stopping Pompey from building an attack whilst Aldershot missed chances to put the tie to bed.
They would pay for those missed chances as Ricky Holmes lofted a ball into the box which was flicked on by Taylor and then headed in at close range by Hollands for the equaliser.
Any likelihood of Pompey finishing the match with a flourish immediately ended as Paul Robinson was sent off for a silly late challenge on the wing which earned him his second yellow card. Ben Chorley was brought on for Holmes to ensure that Pompey didn't concede a third goal.
The final whistle was met by some boos from the Portsmouth fans and they were justified after a terrible second half performance. Had Aldershot held on for the win then there could have been no complaints as they would have deserved it on the day.
Instead, Pompey have been handed a second bite at the cherry following an unacceptable performance which is purely down to attitude. Aldershot wanted it more, won the midfield battle and took advantage of some some extremely bad defending in the full back positions.
Some fans can moan at the referee and the state of the pitch but had the players applied the same amount of effort in today's match as they did in last week's match against Carlisle then they would probably be safely into the second round and wouldn't have a tricky replay to navigate.
And whilst some of the calls for Andy Awford's head are ridiculous it was ridiculous for him to take off Westcarr, who had been more effective than the anonymous Storey, and throw a young midfielder into the mire in his place. The psychological boost Aldershot received from seeing that Awford had admitted his team were being outfought and out-thought by retreating into a negative formation was clear to see.
Still, this is the FA Cup and shocks do happen. Hopefully Pompey will learn from this and realise that no matter who the opposition are, anything less than 100% effort will likely see you get beaten. If there is one positive to come out of this performance is that we're unlikely to see a repeat of it come next week at Aldershot.
So whilst it was a poor showing, be thankful that you don't support Coventry City at this current moment in time!
Pompey Player Ratings
Paul Jones: 6 - No chance with the goals.
Alex Wynter: 3 - Really poor.
Paul Robinson: 5 - Stupid second booking.
Joe Devera: 5 - Not as solid as in previous matches.
Nicky Shorey: 3 - Showed no interest.
Jed Wallace: 6 - Good start and end to the match but faded in the middle.
Danny Hollands: 6 - Spared Pompey's blushes.
Nigel Atangana: 4 - Far too sloppy and sluggish.
Ricky Holmes: 5 - Got little change out of Aldershot's defence.
Miles Storey: 4 - Anonymous apart from two late shots off target.
Craig Westcarr: 6 - Rightfully angry when taken off.
Ben Chorley (Holmes 84): N/A - Shored up the defence late on.
Ben Close (Westcarr 66): 5 - Made a fatal error as soon as he came on.
Ryan Taylor (Atangana 72): N/A - Played his part in the equaliser and posed some problems for Shots defence.