However, victory at the Kassam Stadium is now essential if they are to progress in this year’s competition.
Just like their previous three home legs in the format, the latest entry finished as a draw.
A hugely disappointing outcome for Kenny Jackett’s men, who had taken the lead and also largely been the better team throughout.
Granted, the tie remains wide open as the sides head to Oxford United on Monday for the decider.
Yet this was a glorious opportunity to stake a foothold in the play-off semi-final against stubborn opposition.
Plus the fact the Blues have never scored an away goal in play-off participation will no doubt weigh heavy on the optimism of the Fratton faithful.
Not that Jackett’s men should be condemned for their first-leg performance. Certainly they looked the more threatening side.
Ronan Curtis had deservedly opened the scoring on 32 minutes, collecting Andy Cannon’s pass before finishing from the tight angle.
There were also three strong shouts for a penalty, including a challenge on the Irishman deep into time added on.
The sight of Blues players surrounding referee Gavin Thomas at the final whistle demonstrated what they thought of the latest decision.
As it was, Marcus Browne’s goal on the counter two minutes before half-time ensured a 1-1 draw.
Jackett had sprung surprises with the team selection, particularly the dropping of skipper Tom Naylor in favour of handing Bryn Morris his first outing in 14 months.
Morris can be pleased with his efforts, completing the full 90 minutes alongside Cameron McGeehan in the holding role.
Yet Pompey didn’t quite do enough in the second half to win the fixture, taking until Christian Burgess’ 82nd-minute header to test Simon Eastwood in that period.
Perhaps Oxford will claim a fair outcome, it undoubtedly enhances their own play-off chances having left Fortress Fratton and its 1,108 cut-outs intact.
Still, Pompey have Monday to now focus on - a fixture they must win to reach the Wembley final.
Certainly Jackett’s team selection got the Fratton faithful talking with a raft of surprise selections.
In addition to Naylor being dropped for Morris, Lee Brown was named ahead of Steve Seddon and also handed the captaincy.
Over at right-back, James Bolton had entered lockdown as first choice, yet was deposed by Ross McCrorie for the first leg.
Meanwhile, Ryan Williams, another regular starter previously, made way for Marcus Harness on the right-wing.
There was also a recall for Andy Cannon, operating behind Ellis Harrison, with 14-goal John Marquis on the bench.
Able to name nine substitutes, there was no place, however, for Ben Close, Brandon Haunstrup and Reeco Hackett-Fairchild in the 20-man squad.
In addition, Jack Whatmough was absent as his fiance gave birth to a girl on the morning of the game, while Brett Pitman’s exile continues.
Pompey started the game positively and on six minutes came agonisingly close to taking the lead.
Cannon fed the ball inside to Ronan Curtis, who struck a smart low shot which hit the foot of the right-hand post and bounced out.
Keeper Simon Eastwood was committed, but unfortunately Cannon, following up, couldn’t quite control the ball in front of goal and the move petered out.
That didn’t deter from a bright start for the Blues, comfortably establishing themself as the dominant side in early proceedings.
The hosts were finding space down both wings, with Curtis already suggesting he can make a decent impact through his raids down the left.
On the other flank, McCrorie’s willingness to overlap Harness put him in several promising crossing positions without yet finding the accuracy.
There were also two reasonable Pompey shots for a penalty, on one occasion for handball and the other Burgess appearing to be held at the far post.
On 26 minutes, James Henry’s corner from the right was met with a far-post header from Josh Ruffels which Alex Bass palmed behind.
Moments later there was a flashpoint when Cameron Brannagan’s poor challenge on Harrison incensed McGeehan, who angrily pushed over the Oxford perpetrator.
After referee Gavin Ward was stepped in to quell the subsequent scuffle, both McGeehan and Brannagan were booked.
Pompey took the lead on 32 minutes through Curtis following an excellent flowing move.
Harrison and Cannon were involved in the classy build up, the latter pushing the ball out wide to Curtis on the left wing.
The Irishman then finished from the tightest of angles with his left foot to put the Blues 1-0 up.
Oxford responded positively, with Marcus Browne firing a dangerous delivery from the left across the face of goal, but no-one was able to apply the finishing touch.
The equaliser arrived two minutes before half-time, through a sloppy goal to concede.
Following two Pompey players getting in the way of each other in Oxford’s half, the visitors broke, with Browne running at the defences before firing in a low shot.
It had enough power to beat Bass at his near post and the scoreline was 1-1 going in at the break.
There were no substitutions at the break and once again the hosts began the half in promising fashion.
It prompted Oxford to introduce Mark Sykes for Ben Woodburn on 55 minutes for the first substitution of the match.
The Blues themselves made a double substitution on 63 minutes, with Williams and Bolton replacing McCrorie and Cannon.
Bolton represented a straight swap at right-back, while Williams’ introduction allowed Harness to slip inside and take up Cannon’s number 10 role.
On 72 minutes, Marquis was introduced for Harrison in a straight swap, positioning the Blues’ leading scorer as a lone striker.
Pompey were pushing for a winner and when Curtis laid it inside the box to Brown, his shot deflected off Sykes and into the side netting.
However, Jackett’s men were then threatened on the counter, with Browne bursting forward, only for the skipper to keep calm and produce an excellent block inside the box.
Pompey had a late opportunity when Brown’s free-kick was met with a header from Burgess and pushed around the post by Eastwood for a corner.
It was the Blues’ best goal-scoring opportunity of the half and time was running out to regain their lead at Fratton Park.
As the match entered its 88th minute, Alex Gorrin cynically brought down Curtis as he charged towards the penalty area, however his free-kick was a poor one.
There was late drama when substitute Dan Agyei’s challenge on Curtis sparked more appeals for a penalty, yet nothing was given.
Now the sides do battle on Monday - and Pompey require their first-ever play-off victory.