Yet initial life without the 59-year-old bore no discernible difference.
London Road staged a 1-0 Blues defeat which leaves them tenth in League One as their season continues to splutter out.
There was commitment, but a clear lack of quality and barely a shot mustered on target, despite an improved second half.
Caretaker boss Joe Gallen who himself is scheduled to soon leave, sent out a side featuring a back five, no recognised striker, and armed with a remit to stifle Peterborough.
The design was to contain – and hit on the break through the pace and mobility of Ronan Curtis and Ryan Williams.
That game plan perished after 32 minutes, when Craig MacGillivray punched a corner against Rasmus Nicolaisen, with the ball subsequently bouncing into the visitors’ net.
Certainly up until that point Pompey had frustrated the Posh, prompting them to ditch their own three-man defence during the first half in favour of a back four.
There was even a chance for Williams on the counter attack, only to take a heavy touch as he entered the penalty area with just the keeper beat.
Yet a fifth successive defeat in all competitions was effectively implemented by MacGillivray’s costly error.
The Wembley hero whose saves prevented a rout against Salford was at fault on the return to league action.
Following that moment, Gallen’s men never suggested they were capable of getting back on level terms.
They toiled away, demonstrated effort, but a team which has developed a crisis in confidence in recent months struggled to land a punch.
Not good enough, but that has been a recurring theme for a fair while now.
As a consequence, the once purported automatic promotion challengers are skidding down the league table, with Gillingham and Oxford United now ahead of them.
Gallen opted to make five changes to the side which lost in the Papa John’s Trophy final - while introducing an alternative system.
Employing a 3-5-2, in came Rasmus Nicolaisen, Lee Brown, fit-again Andy Cannon, Ben Close and Ronan Curtis.
They replaced Charlie Daniels, Jordy Hiwula, George Byers and Harvey White, while John Marquis was missing with an ankle injury.
Nicolaisen was recalled to serve in a back three, partnering Jack Whatmough and Sean Raggett.
That left James Bolton and Brown as the wing-backs, with Tom Naylor, Close and Cannon in midfield.
For Close, it represented his first League One start since mid-November against Plymouth, yet reward following his Wembley substitute showing.
Intriguingly, despite Marquis and Ellis Harrison (knee) ruled out, Pompey opted not field a recognised striker.
Hiwula, who started the Papa John’s Trophy final, was dropped to the bench at London Road, with Curtis and Ryan Williams in attack.
Meanwhile, Michael Jacobs was not included in the squad, with Paul Downing 19th man and seen warming up before the game.
When the match kicked off, Siriki Dembele had a chance on six minutes when Frankie Kent flung in a cross from the right.
The winger met it with a header from a decent position, but diverted the attempt comfortably wide when perhaps he should have done better.
Peterborough had started strongly, dominating possession, with the Blues unable to retain the ball in the hosts’ half of the pitch.
It was looking a long night ahead, with Pompey seeking to soak up pressure before hitting on the counter-attack.
That is exactly what happened on 21 minutes, when Williams was released down the left by Cannon and drove through on goal.
However, his last touch on a difficult pitch was a heavy one, the ball bouncing too far ahead of him and gathered by Christy Pym.
The match was proving rather uneventful, not that Pompey would be disappointed with how it had progressed so far, with the scoreline goalless.
In response, Peterborough changed their system to a 4-4-2, with Nathan Thompson moving from one of three centre-halves to right-back.
On 31 minutes, Williams did get a sniff on goal following a long Whatmough throw-in, but Thompson stepped across to block.
There were muted appeals from Curtis, but no foul was apparent – and nothing penalty was given.
However, on 32 minutes, the Posh broke the deadlock following a Harrison Burrows corner delivered from the right.
Craig MacGillivray met it with a punch, but succeeded in diverting it against Nicolaisen and into the Pompey net.
No blame could be attached to Nicolaisen, who could do little to prevent it. Regardless, the hosts were 1-0 up.
At the other end, the Blues won a free-kick on 38 minutes, which Curtis drove right-footed straight at Pym, who dealt with it easily.
Nonetheless, it represented their first attempt on goal during the fixture.
With half-time approaching, Whatmough was left one-on-one with Dembele on the flank, and made sure he wasn’t beaten by bundling over the winger for a booking.
Close, though, was catching the eye, and he combined well with Bolton down the right before putting in a tremendous cross, which was eventually skied by Cannon.
It remained 1-0 as the team headed into the interval, although there were no changes after the break.
On 50 minutes, Williams was fouled by Reece Brown down the left, with Brown’s free-kick into the box challenged for by Nicolaisen.
The defender appealed strongly for a penalty, yet the referee instead awarded a corner from the left.
Pompey were beginning to rally in the second half, though, and when Brown put in another free-kick from the left, Whatmough sent a header wide.
On 61 minutes, Gallen made his first substitution, with Marcus Harness introduced for Cannon.
It was too comfortable for the hosts and Louis Reed saw a shot from distance pushed away by the diving MacGillivray.
On 73 minutes, Gallen made a double change, with Hiwula and Raggett coming off for White and Raggett.
As a result, the Blues switched to a back four as they attempted to find that London Road equaliser.
The second period was clearly an improvement on the opening 45 minutes, nonetheless Pym was barely threatened for all the huffing and puffing.
There was an 86th minute attempt from Curtis, right-footed from well outside the box, but that was straight down the throat of the keeper.
And that was it. Life after Kenny Jackett.
A message from the Editor, Mark Waldron
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