Sydney –

All the Southern Hemisphere powers have something to prove when the Rugby Championship kicks off this weekend, but New Zealand's crisis of confidence in the All Blacks means all eyes will be on their blockbuster opener in Mbombela, South Africa.

Back-to-back tests against the Springboks in their own backyard is far from the dream scenario for a team looking to turn around a poor run of form which has seen New Zealand lose four of its last five matches.

Coach Ian Foster jettisoned two of his assistants amid a bombardment of flak after the July series loss to Ireland, and it is hard to see him survive in the job if the All Blacks lose on Saturday and again at Ellis Park the following week.

The reigning champions have no shortage of world-class players, but the cohesion and calm that usually typifies All Blacks rugby all but disintegrated in the face of a clinical Irish assault in the final two tests of the series.

Jacques Nienaber's Springboks will have watched those matches with great interest and be quietly confident in their own ability to bring pressure after prevailing 2-1 in a tough July series against Wales.

While questions remain over how well the conservative game plan that saw off the Welsh will work against more expansive teams, the world champions will start as favorites to land a fifth Southern Hemisphere title.

Australia, meanwhile, will be relieved not to have to face the back-to-back tests against the All Blacks which usually start their championship, though the tour of Argentina for the first two rounds looks anything but easy for a stuttering side.

Having been outwitted and outmuscled by Eddie Jones's England in their 2-1 July series loss, the Wallabies now face a team mentored by another charismatic former Australia coach in Michael Cheika.

Dave Rennie's side will need to be smarter and more clinical to reap the rewards of their multi-phase attacks against a Pumas side that prides itself on muscular defence and being hard on the ball at the breakdown.

With two home tests against South Africa and a home-and-away Bledisloe Cup series against New Zealand to follow, the Wallabies desperately need a good start in Argentina if they are to have any chance of a first title since 2015.

After a 2-1 July series triumph over Scotland, Cheika will have had the luxury of five straight tests on home soil to work with his side before they head off to New Zealand for their third and fourth round matches.

The Pumas have played entirely on the road in the last two championships — sometimes in the toughest of lockdown conditions — and will be confident of at least a couple of upsets as they build towards next year's World Cup.

World Rugby's campaign to reduce head impacts in the game will undoubtedly carry through to that global showpiece in France, and red and yellow cards could again play a big part in results over the six rounds of the championship.

To mitigate the potential impact of dismissals on the contests, however, governing body SANZAAR has retained the law trial which allows the replacement of a red-carded player after 20 minutes.