John Mousinho’s side travelled to Leyton Orient in the Bristol Street Motors Trophy a little over 48 hours after Sunday’s FA Cup upset.
Yet they would bounce back impressively at Brisbane Road considering the circumstances.
Forced to play 71 minutes with 10 men following Sean Raggett’s red card, a much-changed Blues team dug deep to pull off a battling 2-1 victory.
Christian Saydee opened the scoring shortly before half-time, before Orient substitute Joe Pigott grabbed a 58th-minute equaliser against the club he represented last term.
However, Abu Kamara, the only player to appear in every Blues match this season, secured victory in the 74th minute as the Blues won their group to reach the knock-out stages.
Certainly there was plenty to like about the manner of performance from a side containing 11 changes from Sunday.
Kusini Yengi provided two assists, Harry Jewitt-White shone on a rare outing, while Denver Hume recovered from a shaky start to establish himself as a solid performer on his first competitive outing for seven months.
For those noisy 1,065 away supporters in a 2,371 crowd, it was the opportunity to sing about Wembley, barely two days after another route was ended.
And Pompey are back up and running with a morale-boosting response ahead of Charlton’s crucial Fratton Park visit on Saturday.
Mousinho had opted to rotate all his team for the Brisbane Road encounter, with the out-of-favour Hume a surprise choice at left-back, representing his first competitive outing since Morecambe in April.
Elsewhere, Hayling Island’s Jewitt-White made his third career start for Pompey, lining up in the centre of midfield alongside Ben Stevenson.
Gavin Whyte was also presented with the opportunity to impress as he strives to turn around a disappointing start to his Fratton Park career.
In addition, there were appearances for Ryan Schofield, Zak Swanson, Raggett, Ryley Towler, Saydee, Yengi and Abu Kamara.
Meanwhile, Academy trio Koby Mottoh, Sam Folarin and Mitch Aston were among the substitutes, along with the experienced heads of Will Norris, Joe Rafferty and Conor Shaughnessy.
When the match got underway, Kamara’s anticipation earned the visitors an early opportunity when he intercepted a backpass inside the box.
The winger attempted to find Jewitt-White with a pass, yet couldn’t quite succeed, and the clearance hit him while on the floor to give Orient a goal-kick.
On eight minutes, Theo Archibald got the better of Hume down the right to break inside the Blues’ box, but Raggett stepped up to snuff out the danger and clear.
Hume was having a difficult start defensively and committed his second foul inside the opening nine minutes, yet, moments later at the other end, put in a dangerous cross from the left.
The Blues were reduced to 10 men on 19 minutes when Archibald charged towards the penalty area and Raggett brought him down.
There was no spot kick, with the offence committed just outside the area, but the skipper couldn’t escape referee Stephen Parkinson’s red card as Orient were handed a numerical advantage.
George Moncur took the resulting free-kick, a powerful effort which drew a good stop from Schofield before the danger was cleared.
In the 31st minute, Schofield had to produce a finger-tip save from Aaron Drinan’s angled shot from the right, pushing the ball just past the post to keep the game goalless.
Yet Pompey should have taken the lead on 34 minutes following lovely play from Whyte inside the box.
The winger cleverly flicked the ball past his man and then ran around him to retrieve it, before pulling a cross back from the right which was heading into the path of Jewitt-White.
However, Saydee got in the way, intercepting it before firing a wild left-footed shot wide of a gaping goal, with Jewitt-White standing with arms aloft questioning why he hadn’t left it to the teenager.
Saydee made amends, though, in the 44th minute to cap an excellent team move and hand the Blues the lead.
Whyte started it off, feeding Saydee, who found Jewitt-White on the overlap down the right and his low pass was collected at the far post by Yengi.
Despite having to readjust his body to receive the pass, the Australian had the calmness and presence of mind to roll it to Saydee, who twisted and turned before rolling a right-footed pass into the far corner of the net.
It was the second goal of the ex-Bournemouth man’s Blues career and certainly a welcome confidence boost.
Orient made a double substitution at the break, with former Pompey loanee Joe Pigott and Ethan Galbraith introduced for Ed Turns and Archibald.
They almost levelled on 48 minutes when Drinan’s cross from the right was flicked goal-wards by Ruel Sotiriou, only to strike the right-hand post and bounce clear.
Orient levelled on 58 minutes when Jayden Sweeney’s cross from the left was controlled by Pigott and he was given acres of room to then swivel and fire home a finish past Schofield.
Mousinho made his first substitution on 64 minutes, with Terry Devlin coming on for Whyte, who had enjoyed some encouraging moments.
Pompey regained their lead on 74 minutes, with a well-taken goal from Kamara.
Stevenson intercepted the ball and laid it to Yengi, who calmly laid into the path of the Norwich loanee charging on his outside, before netting with a left-footed finish.
The 10 men were now leading 2-1 and had 16 minutes to negotiate - with a place in the next round of the Bristol Street Motors Trophy at stake.
On 79 minutes, Schofield pulled off an excellent stop at the back post from Drinan’s header after a corner from the left, afterwards requiring treatment, but was able to continue.
Mousinho made a double substitution on 85 minutes, with Folarin and Joe Rafferty introduced, marking the former’s first-team debut.
They helped their team-mates negotiate six minutes of time added-on to secure victory – and progress in the one cup competition this week.