Australia v South Africa, 3rd Test, Perth, 1st day November 30, 2012

South Africa lose their middle-order mettle

The visitors have been hampered by a new problem in this series - a lack of consistency in the middle order - and although Faf du Plessis' outstanding start to Test cricket has offered some solace there remain plenty of issues

Limp middle-orders used to infect South Africa's limited-overs teams. It was the reason they failed at the 2011 World Cup and many a tournament before that, but it was not a disease that spread to the longer format. There a mixture of dynamism and dependability existed. Both those are qualities that are absent in it on this tour of Australia.

Of the five innings South Africa have batted in so far, the middle order has let them down every time. In Brisbane they lost 4 for 52 in the first innings and 3 for 63 in the second. In Adelaide, the collapse was more dramatic when five wickets tumbled for 17 runs on the third day.

The six overs after lunch in Perth saw three wickets fall as Hashim Amla, AB de Villiers and Dean Elgar were all dismissed for the addition of only 12 runs. It is this folding that will seem the most glaring because it resulted in a below-par score despite the later recovery.

The inability to minimise risk is the root cause for the wobbles illustrated by two of the three dismissals in Perth. Amla was run-out after answering a de Villiers call that should have been more circumspect. De Villiers himself was on the receiving end of a good ball that swung away late to find his edge but then Elgar's inexperience showed in his short selection. He played an unnecessary pull after being primed by a series of pitched up deliveries from Mitchell Johnson.

Jacques Rudolph, who was dropped for this match, was guilty of exactly the same thing in the previous two Tests. His could not blame it on inexperience, though, but a technical flaw. Rudolph played Nathan Lyon in the air in both Brisbane and Adelaide to further underline his vulnerability against offspin and he was left out of the XI to play the deciding Test.

Rudolph's average in his last eight innings was 26.87 and he was an obvious weak link. Because of that South Africa have needed seven batsmen, not to lengthen the line-up as they would have us believe but to recover. In Faf du Plessis they have found an able Mr Fix It. He has the temperament and confidence of someone whose Test career is much older but even his patch-up job on the opening day here could not harden the soft middle order.

Just a year ago, South Africa had players who could act as solidifying agents. With de Villiers at No.5 with Ashwell Prince at No.6 there was a combination which could be both sensational and stable. Neither are around anymore: Prince literally so and de Villiers not as we knew him.

Prince was dropped after the Boxing Day Test last year, even though he scored a half-century the match before that. He was retained on national contract but has been given no indication that he will play for his country again.

De Villiers has become a shadow of the batsman he once was. Although his resilience remains as both his innings in Adelaide showed, his flamboyance has gone. Despite his insistence to the contrary, becoming the full time wicketkeeper has affected his batting and he has not scored a half-century in nine innings since taking over the role.

On most occasions he has managed a start but been unable to convert and it appeared to be a problem with patience. Adelaide debunked that myth. He batted for over four hours and faced 220 balls for his 33. His forward defensive made more appearances in that innings that it has done in the ten before them and it was as unbreakable as the wall he had erected around his state of mind.

Du Plessis said de Villiers was so defensive in his approach it took even him by surprise. When he joined his school-friend and team-mate at the crease, he hoped they could stay positive at first but de Villiers turned down singles they would normally have run for fun. They both knew they could not present even a sliver of an opening to Australia and de Villiers took that instruction very seriously. As a result, the pair "blocked balls we could have hit for a few," as du Plessis later said.

De Villiers emerged out of that innings with proof that he had the stamina to bat for a long period and that he was able to do that without presenting the chances he had before. Not even a week has passed since that day and de Villiers has reverted back to the player who chased a short and wide Peter Siddle delivery in Brisbane.

His running out of Amla and subsequent succumbing to a ball he could have got behind, albeit it a good one, left South Africa facing a paltry first innings total. While Elgar also contributed to that, he cannot be judged yet. To walk in on debut with the team in trouble is difficult. Although he had du Plessis to draw inspiration from, his duck, notable for being the first by a South Africa Test debutant since 1998, will not close his door. A player of the experience and calibre of de Villiers though, should have taken more responsibility.

That could be what the South Africa middle order currently lacks most: someone to front up. With a top four that carries the heavyweight credentials of Graeme Smith, the form of Alviro Petersen who has scored three hundreds and two fifties this year and the aura of Amla and Jacques Kallis, it is easy for the rest to think they won't have much to do.

But they will and they need to be properly equipped for that. For as long as de Villiers continues to don the gloves the decision between six and seven batsmen remains unresolved, as does the identity of those players, which is far from the ideal position for solidity.

Firdose Moonda is ESPNcricinfo's South Africa correspondent