Rome wasn’t built in a day but if it were to be constructed on the foundations of this Southampton defence, it’d certainly crumble pretty quickly.

We didn’t learn a great deal more than what we were already aware of as the Saints fell to a 1-0 defeat at Cardiff. Ralph Hasenhuttl was subject to the misfortune of experiencing just what the St Mary’s faithful have over the past two seasons.

In a closely-contested fixture, Southampton had plenty of the ball and put together some neat passing moves. There was little attacking penetration but there was, at the very least, a game-plan.

Hasenhuttl’s side set up to overload Neil Warnock’s men in central areas, as depicted by the manager’s choice to use a midfield diamond consisting of Oriol Romeu, Mario Lemina, Pierre-Emile Hojbjerg and Stuart Armstrong.

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There were periods when Saints would intensely press before attempting to distribute towards the full-backs, who had the freedom of the flanks to roam within.

Unfortunately for Southampton, the quality of full-back appeared to drag them down. Positionally, Matt Targett and Yan Valery struggled. They were flat-footed on several occasions and failed to read the game well enough, hesitating in far too many key moments.

Hasenhuttl attempted to change Saints’ defensive fortunes. Valery was given his second Premier League start and Jannik Vestergaard and Jan Bednarek took the respective places of Maya Yoshida and Jack Stephens.

As has already been alluded to, however, Hasenhuttl got VIP access to the calamitous show that is the art of how not to defend, delivered expertly by £18 million summer signing Vestergaard.

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The Danish defender was awarded a golden opportunity to impress his new boss and was, in no uncertain terms, terrible. He was clumsy, ponderous in possession and ultimately, it was his costly error that has plunged Southampton into further dismay at the bottom end of the table.

Hasenhuttl has shown on numerous occasions in Germany just how tactically adept he is, from taking games to opponents to shutting up shop, grinding out results.

However, the new man was totally helpless to prevent Southampton’s capitulation in Wales and watched on in dismay, just as his players did, as Vestergaard delicately played Callum Paterson through on goal in the final stretch of the fixture.

Tactics go out of the window when individual errors to this extent take place, especially in a game of such magnitude.

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Vestergaard, who the club broke their defensive transfer record for, is unfortunately now looking increasingly like a certain other clumsy Saints centre-back, but £3 million more expensive.

Each one of Southampton’s central defenders have played some part this season and not one has convinced in the slightest. They are all hesitant in possession and are prone to unforgivable individual errors.

Saints are now five points adrift of newly-promoted Cardiff and languish in 19th place on the Premier League table.

Hasenhuttl often draws on the phrase that his sides never lose; they either win or they learn. But for as long as Southampton’s defenders continue to prove themselves as liabilities, it’s hard to see how the inevitability of defeat will be avoided.