Pompey’s disappointing start to the league season continued as a late penalty saw them slip to defeat at Wycombe.
Adebayo Akinfenwa netted the only goal of a game that was largely lacking in quality and saw both sides finish with 10 men.
Nnamdi Ofoborh was dismissed for a late challenge on Tom Naylor, with Ellis Harrison's reaction in an ensuing melee earning him a second booking.
Substitute Brett Pitman had the best chance to secure a fourth successive League One stalemate, but headed against the woodwork.
Kenny Jackett made four changes from the side that drew with Burton on home soil earlier in the week.
Oli Hawkins made his first start of the season alongside Christian Burgess in the centre of defence, with skipper Naylor moving back to midfield.
James Bolton came in at right-back, Andy Cannon returned to midfield and Ellis Harrison joined the forward line.
Paul Downing, Ross McCrorie, Ryan Williams and Pitman were the players to make way, all dropping to the bench.
There were a couple of former Fratton loanees in the hosts’ squad, with keeper Ryan Allsop starting and David Wheeler named among the substitutes.
It is fair to say that the opening 45 minutes will not live long in the memory of anyone present in Buckinghamshire.
Neither keeper had any meaningful save to make in a scrappy, attritional contest that was lacking any kind of attacking flair.
Naylor sliced an early attempt wide, while Ronan Curtis also failed to find the target with a shot on the half-volley.
The only scare for the visitors was when Craig MacGillivray failed to hold Allsop’s long punt up the pitch, but the referee quickly blew for a foul on the Blues stopper.
Pompey’s best chance of the half came when Ben Close slipped a pass through to Harrison, with the forward bending a shot into the side netting.
He then picked up the game’s first booking, although it was slightly unfortunate, with a slip sending him careering into the imposing figure of Akinfenwa.
The Chairboys were then forced to make a change when captain Matt Bloomfield – who has already suffered from concussion this term – was replaced by Ofoborh following a clash of heads.
One bright spot was the display from Hawkins, who was looking as natural a defender as anyone on the pitch.
But there was still not much to talk about in terms of attacking, with Close skewing wide from long-range after a poor Allsop clearance had left the net unguarded.
Everyone seemed ready for the interval, but that was delayed by an injury to stand-in Wycombe skipper Joe Jacobson.
Jamie Mascoll replaced him and the armband changed hands yet again, although Akinfenwa struggled to get it around his arm.
Half Time: Wycombe 0 Pompey 0
Both sides looked more purposeful once the action restarted, but that all-important final ball was still lacking.
The game then exploded into life following a late challenge by Ofoborh that led to both teams being reduced to 10 men.
Referee Sebastian Stockbridge immediately brandished a red card to the Wycombe substitute, who was in tears as he left the pitch.
There was then plenty of pushing and shoving from both sets of players, resulting in bookings for Akinfenwa and Christian Burgess.
And the final yellow was shown to Harrison – and it was his second of the afternoon, resulting in a walk down the tunnel.
Once the football restarted it was Pompey on the attack and a John Marquis cross had to be nodded behind before Curtis could reach it.
A free-kick from the left by Curtis was then parried away by Allsop and Burgess’ follow-up was deflected wide.
Stockbridge was drawing ire from both sets of supporters, not helped by some soft free-kick decisions for both sides.
Pitman replaced Bolton as Jackett looked to freshen up his attacking options, with both sides then going close to breaking the deadlock in quick succession.
Wycombe were first to try their luck and MacGillivray made a smart stop to deny Scott Kashket before the ball was hacked to safety.
And Pompey went straight up the other end of the pitch, with a long-range effort from Close deflected inches past the post.
Then, after Pitman was booked for a foul on Dominic Gape, a Mascoll free-kick was turned behind by MacGillivray.
But the Chairboys took the lead on 83 minutes after Naylor had been penalised for handling from a Nick Freeman corner.
Stockbridge pointed to the spot and, although MacGillivray went the right way, Ainfenwa’s penalty nestled in the bottom corner.
Pompey almost levelled soon after when Pitman met Brandon Haunstrup’s delivery, but his header hit the crossbar.
The visitors kept pushing throughout seven minutes of stoppage-time, but they were unable to find a late leveller.
Wycombe (4-2-3-1): Allsop; Grimmer, Stewart, Charles, Jacobson (Mascoll 45+2); Gape, Bloomfield (c) (Ofoborh 22); Kashket, Freeman, Onyedinma (Pattison 72); Akinfenwa
Goals: Akinfenwa 83 (pen)
Sent off: Ofoborh
Booked: Akinfenwa
Subs not used: Yates, Phillips, Wheeler, Jarvis
Pompey (4-3-3): MacGillivray; Bolton (Pitman 70), Hawkins, Burgess, Haunstrup; Close, Naylor (c), Cannon; Harrison, Marquis, Curtis
Sent off: Harrison (two yellow cards)
Booked: Burgess, Pitman
Subs not used: Bass, Walkes, Downing, McCrorie, Evans, Williams
Referee: Sebastian Stockbridge
Attendance: 7,688 (2,125 Pompey fans)