A brace of Colby Bishop penalties was not enough to prevent Pompey from falling to their first League One defeat of the season at Ipswich.
The striker kept his cool to twice draw the visitors level, cancelling out strikes from Marcus Harness and Freddie Ladapo.
But the second one was immediately followed by an unfortunate Wes Burns goal that ensured the Tractor Boys claimed all three points.
Danny Cowley made one enforced change from the side that dramatically drew with Plymouth a fortnight earlier.
Tom Lowery hurt his hamstring against Argyle and was replaced in the centre of midfield by Joe Morrell.
Joe Pigott was not allowed to feature against his parent club, while there were a couple of familiar faces in the opposition line-up.
Former Pompey forwards Conor Chaplin and Harness both started for Ipswich, but Gassan Ahadme was ruled out through injury.
The visitors had to withstand plenty of first half pressure and Chaplin could only swipe at thin air after being found in the box by Burns.
Tyreece John-Jules then failed to make a clean connection with Leif Davis’ low cross and the ball ricocheted off Sean Raggett, flying just past the post.
The Tractor Boys almost broke the deadlock from the resulting corner, with Chaplin’s effort cannoning back off the woodwork.
Pompey did start to enjoy a bit more possession as the half progressed, although were unable to test Christian Walton.
And hearts were in mouths at the other end, as a shot from Harness struck Connor Ogilvie and looped onto the roof of the net.
But the home side did break the deadlock on 25 minutes after stealing possession in the centre of the pitch.
Chaplin was able to thread a pass through to Harness, who had time and space to run forward and slot past Josh Griffiths.
It might have got even worse for the Blues, but Griffiths just able got to the ball before John-Jules could reach it.
Pompey were then gifted a chance to level the contest when Owen Dale’s pass for Dane Scarlett caught out Luke Woolfenden.
That allowed the on-loan striker to get into the area, where he was sent crashing to the turf by Walton.
Referee Charles Breakspear immediately pointed to the spot and BISHOP slotted the penalty underneath the keeper's dive.
Ipswich might have restored their lead just before the break, but Griffiths was equal to a well struck Burns effort.
Half Time: Ipswich 1 Pompey 1
It was the visitors who made the brighter start when the action resumed and a 30-yard Marlon Pack free-kick was beaten away by Walton.
But it all started to get a bit scrappy as the second half progressed, with both sides conceding niggly free-kicks.
Cowley freshened things up with a double switch on 66 minutes, as Josh Koroma and Morrell made way for Ronan Curtis and Ryan Tunnicliffe.
The contest was certainly not as lively since the restart, with both sides struggling to find any attacking rhythm.
Ipswich made a couple of changes of their own and one of their newcomers made an immediate impact.
Davis sent a low ball into the box from the left and Ladapo fired it into the top corner just a few seconds after entering the pitch.
It was the start of a crazy period that saw Pompey level with another spot-kick, only for Ipswich to quickly retake the lead.
Clark Robertson’s throw had found Curtis just inside the box and the substitute was tripped by Sam Morsy.
BISHOP again stepped up to take the penalty and this time he sent Walton the wrong way before racing off to celebrate with the jubilant travelling fans.
But their joy was short-lived as Kyle Edwards raced down the left and his cross struck Ogilvie, looping in the air and giving Burns a simple headed finish from a yard out.
Reeco Hackett and Michael Jacobs were both brought on for the closing stages, as Pompey tried to fight back for a third time.
Ipswich fans slowed things down by refusing to return the ball when it went out of play, only to then gasp in astonishment when an additional seven minutes were displayed.
But despite committing plenty of men forward as the seconds ticked down, Pompey were unable to find another leveller.
Ipswich (3-4-2-1): Walton; Donacien, Woolfenden, Edmundson; Burns, Evans, Morsy (c), Davis (Vincent-Young 90+7); Chaplin (Ball 82), Harness (Edwards 73); John-Jules (Ladapo 73)
Goals: Harness 25, Ladapo 74, Burns 80
Subs not used: Hladky, Keogh, Jackson
Pompey (4-4-2): Griffiths; Ogilvie, Morrison (Hackett 87), Raggett, Robertson (c); Dale (Jacobs 89), Pack, Morrell (Tunnicliffe 66), Koroma (Curtis 66); Bishop, Scarlett
Goals: Bishop 32 (pen), 79 (pen)
Booked: Scarlett, Robertson
Subs not used: Oluwayemi, Swanson, Mingi
Referee: Charles Breakspear
Attendance: 28,434 (1,941 Pompey fans)