The Portsmouth centre-back partnership that still has a lot of convincing to do

All three goals conceded before half-time at the Lamex Stadium were glaringly avoidable as members of the Fratton faithful watching on from home couldn't quite believe what they were witnessing.

While Kenny Jackett knew his side's performance at the back was sloppy in the 3-3 draw, he nevertheless retains confidence those who featured can lead the Blues to League One promotion this term.

However, doubts remain whether Paul Downing and Sean Raggett are suited to forming a partnership capable of providing Pompey with the defensive backbone required.

Downing has so far been handed the assignment of replacing the departed Christian Burgess, despite being left in the cold for the majority of his maiden season on the south coast.

And Raggett continues as a first-team regular after joining on a permanent basis, having scored two goals in 38 games during his season-long loan from Norwich last term.

At Stevenage, it was just the fourth time the duo had featured in the centre of the Blues defence together.

They've yet to suffer defeat when playing alongside each other.

But performances have been unconvincing for the most part.

The first time they were paired together for Pompey was that infamous night against Coventry just more than a year ago.

Raggett, in particular, was shaky as the Blues surrendered a 3-1 lead to draw 3-3 against a Sky Blues side that ended the game at Fratton Park with nine men.

Their next outing together was a victory over Crawley in the Leasing.com Trophy. In fairness, few errors were committed as Brett Pitman's strike secured Pompey a 1-0 win.

But it was at Walsall in the second round of the competition when Downing and Raggett endured a catastrophic 90 minutes.

Just before half-time, Downing's poor attempt of a chested pass put the visitors in all sorts of danger.

Raggett then hacked down Rory Gaffney, with the referee awarding the Saddlers a stonewall penalty.

Not for the first nor the last time, Craig MacGillivray was the Blues' penalty hero, saving the duo’s blushes when he thwarted Elijah Adebayo's spot-kick.

There was to be more incohesion in the rearguard in the second period, though.

This time, it was Downing who committed a foul inside the area when he bundled into the back of Rory Holden, after getting on the wrong side of his marker.

Ex-Pompey striker Caolan Lavery made no mistake and fired home from 12 yards to set up a nervy finish, although the Blues did hold on.

That was to be Downing's final appearance for Pompey before his comeback at Stevenage.

And after the departure of Burgess, there have been concerns raised by supporters whether the Blues will be able to cope without him.

That sentiment certainly hasn't diminished after the duo’s display against Boro. If anything, it’s been reaffirmed.

Both Downing and Raggett are decent League One centre-backs.

The latter demonstrated that when he settled down at PO4 last season during his season-long loan. His arrival on a permanent basis wasn't disputed by many.

Downing, meanwhile, played a key role to get Blackburn promoted in 2018 and helped Doncaster reach the play-offs a year later.

When he moved to Pompey on a free transfer, there were few grumbles.

However, concerns remain whether they're capable of forming a meaningful and effective partnership.

Jackett's still in the market for a left-sided centre-back as he stays patient in his bid to land the best calibre of player available before the transfer window shuts on October 16.

In addition, Jack Whatmough continues to regain fitness after recovering from a third serious knee injury.

Should he get back to his best then he’ll be tough to keep out of the team.

But If Raggett and Downing are to continue as the Blues’ first-choice centre-back pairing, then they must quickly convince.

Otherwise, one will likely find themselves jettisoned from the starting XI.

Jackett can be ruthless when it comes to team selection, after all.