Brett Pitman's late spot kick ensured Pompey remained unbeaten in League One despite dropping two points to winless Shrewsbury at Fratton Park.
Kenny Jackett's men began brightly in the first half without really creating anything but the visitors soon grew into the game and soon fired a couple of warning shots off target.
Their two best chances came late in the second half as Tom Naylor had the ball robbed from him by Oliver Norwood and his through-ball to Lenell John-Lewis saw the Shrews striker one-on-one with Craig MacGillivray only to blast his shot over the bar.
Then, Anthony Grant should have scored from close range but instead also managed to find the Fratton End crowd instead of the back of the net.
Jackett made a couple of changes at the break with the disappointing Andre Green and shackled Ben Thompson making way for David Wheeler and Ben Close as Pompey took control of the second half without really testing Joel Coleman.
In fact, the only time the Shrews' keeper was really tested was when he pushed away Gareth Evans' header in the box having earlier dealt with his free kick not long after the restart.
Shrewsbury themselves didn't look like scoring despite having a strong penalty appeal waved away by referee Charles Breakspear when it seemed like Lee Brown fouled Alex Gilliead in the box.
Unfortunately for Pompey, the visitors were gifted the opening goal when a disastrous defensive header from Christian Burgess saw the ball land at the feet of Greg Docherty who had the simple task of slotting the ball into the corner.
Pompey then had a strong penalty appeal waved away of their own when Pitman was wrestled to the ground although he was never going to reach the cross intended for him.
However, Breakspear did point to the spot not long from time but only when his assistant suggested that the foul by Gilliead on Nathan Thompson was inside the box rather than outside.
Pitman stepped up and blasted the ball home for the equaliser but there were no other chances and both sides had to settle for a point after a match that was tedious to watch and ruined by the awful Breakspear who incurred the wrath of everyone in the ground.
On another day Shrewsbury may well have had a penalty. Those in the Fratton End would have been too far away to see the incident but those closer to it have suggested that the Shrews should have had a spot kick.
Pitman probably should have had one too after being taken down in the box regardless of where the ball was going whilst the penalty call on Gilliead was correct as Thompson was just inside the box when the foul was committed.
That shouldn't detract from the multitude of other decisions Breakspear got wrong, not for the first time at Fratton Park, but then his wretched performance shouldn't detract from a sub-par Pompey performance in the first half, either.
Shrewsbury had clearly done their homework as Ben Thompson was given no room to work his magic but his midfield partners in Evans and Naylor certainly didn't help matters by losing the ball constantly. For all of Green's hype, he soon fizzled out after a bright start but it would be unfair to judge him on one half of football.
Poor Oli Hawkins did his best to hold the ball up but his team-mates didn't often provide him with an option going forward and even when he was replaced with Pitman, the latter could do nothing with the aimless hoofs up to him which were easily dealt with by the physical Shrews players.
This game was supposed to be a test of Pompey's squad depth and they failed that particular test as it could be argued that they hugely missed both Jack Whatmough and Ronan Curtis whilst their replacements were either culpable for the goal conceded or didn't make an impact going forward.
The question on whether Pompey are capable of beating imposing sides reliant on more direct and time-wasting tactics remains to be answered and the next home game is against similar opposition in Wycombe Wanderers.
At least, looking on the bright side, Portsmouth drew a game they looked like losing and are still in second place in League One ahead of the first real test of the season when Pompey go to Peterborough for an early top-of-the-table clash at London Road.
Pompey Player Ratings
Craig MacGillivray: 6 - Nothing much to do.
Nathan Thompson: 6 - Lost a few battles defensively but ultimately won the penalty for the equaliser.
Christian Burgess: 5 - Solid first half but kept playing the aimless long ball in the second and, of course, made the glaring error for their goal.
Matt Clarke: 6 - Not at his best and even gave the ball away occasionally.
Lee Brown: 7 - Decent showing as usual.
Ben Thompson: 5 - Closed down too quickly.
Gareth Evans: 6 - Improved greatly in the second half.
Tom Naylor: 5 - Lost the midfield battle.
Jamal Lowe: 6 - Well shackled by Omar Beckles for most of the game.
Andre Green: 5 - Disappointing league debut.
Oli Hawkins: 7 - Did the best he could.
Ben Close (B. Thompson 46): 6 - Balanced the midfield.
David Wheeler (Green 46): 6 - Looked threatening at times.
Brett Pitman (Hawkins 67): 7 - Decent penalty under pressure but lacked service.