Pompey were denied the opportunity to go top of the League One table after being held to a goalless draw by Cheltenham at Fratton Park.
Regan Poole went closest to securing the win by heading against the post, but most of the Fratton Park action took place on the sidelines.
An assistant referee went off injured in each half, meaning that a qualified spectator had to be called from the stands in the second half to run the line.
John Mousinho named a starting line-up that was unchanged from the midweek home victory over Exeter.
There was one switch on the bench, however, where a fit-again Paddy Lane replaced the injured Kusini Yengi.
The early rain had given way to a lovely sunny afternoon on the south coast and there was a perfectly observed minute’s applause before kick-off.
It was to remember Pompey fan and Dunkirk veteran Lawrence Churcher and former skipper Brian Snowdon, who both passed away recently.
When the action started, the hosts showed an intent to get forward, while their opponents looked to capitalise on the break.
But clear-cut chances were at a premium during the first half, with Will Goodwin’s curler into the arms of Will Norris as close as the Robins came to scoring.
Pompey were looking more likely to break the deadlock and when Connor Ogilvie’s cross was headed clear, Joe Rafferty hit a low volley that Luke Southwood got down to save.
A free-kick from Rafferty was then nodded into the mixer by Poole and back-heeled narrowly wide by Alex Robertson.
Any rhythm picked up was disrupted on 35 minutes, however, when one of the referee’s assistants pulled up injured.
It meant that, for the second game in succession, the fourth official had to take over running the line duties.
Pompey did have one last chance after stealing back possession in stoppage-time, but after swapping passes with Robertson, a shot from Ogilvie was easily dealt with by Southwood.
Half Time: Pompey 0 Cheltenham 0
There was a clear sense of more urgency from the hosts when the action restarted and a corner led to Marlon Pack seeing a shot blocked against his former club.
The move was still alive, though, and when Gavin Whyte picked out Poole in the box, his header hit the inside of the post and landed in the arms of a grateful Southwood.
Cheltenham then had a chance on the break, but Aidan Keena took to long to get his shot away and eventually scuffed it wide.
A bizarre moment then occurred when another assistant referee was unable to continue and the referee had to stop proceedings.
It led to a call going out for a qualified match official to make themselves known and eventually, supporter Julian Browning appeared from the stands to take over running the line.
There was a lengthy delay, though, meaning both sides had to warm-up again before the action could finally restart.
Pompey soon had an opportunity to forge ahead, as 20-yard free-kick from Robertson flashed inches over.
Mousinho freshened things up with a double switch, as Jack Sparkes and Abu Kamara came on for Anthony Scully and Whyte.
The long delay earlier in the half meant that 21 additional minutes were displayed – and that was only going to increase after Keena required treatment.
Christian Saydee was brought on in an attacking change, with skipper Pack the man to make his way off the pitch.
Pompey kept trying to break down their stubborn opponents and Ogilvie volleyed narrowly over after his initial effort from a Rafferty delivery was blocked.
The visitors, meanwhile, were looking to use up as much time as possible, with Southwood booked for wasting too much of it.
Saydee eyed up a shot when Rafferty’s deflected cross fell for him in the box, but the substitute could not make a clean connection and the ball ballooned over.
And although they kept pushing forward in the closing stages, the Blues were unable to force a winner.
Pompey (4-2-3-1): Norris; Rafferty, Poole, Shaughnessy, Ogilvie; Morrell, Pack (c) (Saydee 90+6); Whyte (Kamara 82), Robertson (Lane 90+22), Scully (Sparkes 82); Bishop
Subs not used: Schofield, Swanson, Raggett
Cheltenham (3-4-3): Southwood; Long (c), Davies, Freestone; Smith (D’Auria-Henry 51), Sercombe, Thompson (Adshead 90+4), Ferry (Chapman 90+13); Street, Keena (Williams 90+4), Goodwin
Booked: Sercombe, Thompson, Southwood
Subs not used: Harris, Bradbury, King
Referee: Ben Toner
Attendance: 17,454 (260 away fans)