All four home nations know for all that has occurred in the previous three weeks, their result on this fourth weekend will determine the overall feeling of progression going into the Six Nations and, of course, a World Cup year.
They simply all need to perform this weekend - one which is always the hardest to predicted due to a combination of injuries, fatigue and squad rotation which can render what's happened in the run-up to be far less relevant.
A game that always feels like it could go either way, the rivalry and history between these two fierce rugby nations almost guaranteeing a spectacle of sorts.
This time, though, all analysis of form and facts points to an England win, and it's only history that prevents me being absolutely confident in the Red Rose delivering a big one, too.
As we discussed in my week four talking points, Australia have had a miserable year, sliding down the rankings. They appear to have lost the ego and confidence that always drove them to big performances when needed.
This is the game for Wales - win and it's full steam ahead for the Six Nations and a charge to winning their first World Cup; lose and question marks will remain about their mentality, game plan and execution against the very best sides in the world.
As expected, coach Warren Gatland has made 14 changes from the side that eventually saw off Tonga with a big scoreline. He reverts back to the outfit that ground out their historic win over Australia, with only the injured Leigh Halfpenny missing.
Wales are now good enough physically and mentally to beat an excellent Springboks side, but I worry about their momentum with all these changes. Remember they didn't play their best team against Scotland at the start of November, so their 'best' XV have only featured in that important, but stuttering and under-performing win against a drowning Australia.
Two of 2018's form teams meet at the Aviva Stadium on Saturday, with both boasting an identical record - won 10, lost one.
Ireland recorded their historic win over New Zealand last weekend, to full confirm their status as genuine World Cup contenders. But the USA, determined to become a Tier One rugby nation, have also had huge results, beating Scotland in the summer and Samoa two weeks ago.
That has come at a cost and the USA have major injuries for this one, and while Ireland make big changes they will still be too strong.
Posted at 1445 GMT on 22/11/18.