PERTH — It is a measure of just how much Test cricket has changed in the past five years that South African supporters — and even players — are not certain of victory, despite setting Australia a preposterous run chase target of 632 to win.

History suggests it is impossible — the highest fourth-innings run chase in over 135 years of Test cricket is 418. Only twice has a target of more than 400 been successfully chased. But what that list does not show is the amount of time available to chase the runs.

In the context of fourth-innings run chases, the fact that Australia still have two days left to change history is just as absurd as the number of runs they need. As Mickey Arthur said after yesterday’s third day: “If we bat until the end of the match we’ll win.”

It was exactly what he told the Proteas four years ago when they were left with five sessions to chase 414, and did so while losing just four wickets. Hashim Amla spoke of “playing a few one-day shots” to hit the ball into gaps rather than where the fielders were placed.

One-day cricket has been around for more than 40 years — it is more the advent of Twenty20 cricket that has taught batsmen to invent ways to hit the ball into unguarded areas, and quickly. A decade ago the thought of chasing 400 was absurd. Now, here we are, wondering whether 632 can be chased down.

That in itself is a triumph for Test cricket: that it is strictly regulated to five days of 90 overs.

But even in the days of Timeless Tests, no such totals were reached. England, however, did come desperately close to reaching the 696 they needed at Kingsmead in 1939 when play was finally called off after nine days with the tourists on 654/5 because they needed to catch a train to Cape Town where their ship was leaving for home!

Amla’s batting in this Test match will live long in the memory, longer even than AB de Villiers’s brilliant 169 because the brutality of his assault on the Australian bowlers started with the match still in the balance. He reached the 90s from fewer than 70 deliveries: “I was lucky because there were a few loose deliveries which I was able to get away quite early on and the momentum continued from there.”

What absolute nonsense!

Amla tore into Australia’s bowlers from the moment he arrived at the crease. It was the most calculated and savage attack launched by a Proteas batsman in the past 21 years, discounting those which came when the match, and the bowlers, were already ” gone”.

De Villiers was the first to admit his arrival at the crease, with the scoreboard reading 287/3, was very different to Amla’s at 28/1.

Both batted fearlessly, but only one did so when there was still something to fear.

One of Australia’s longest-serving and most respected cricket writers compiled a list of “great innings played by tourists in Australia” over the past 40 years.

Brian Lara’s 277 in Sydney in 1997, Sachin Tendulkar’s 241 in Sydney in 2004, Michael Vaughan’s 145 in Melbourne in 2002, Roy Fredericks’s 169 in Perth in 1975, and JP Duminy’s 166 in Melbourne in 2008 featured in the article.

Amla’s 196 in Perth this year was at the top of the list.

As De Villiers confirmed, neither he nor Amla would place their efforts among their favourites if South Africa do not win. And understandably.

But despite everything we have witnessed over the past decade, and despite the doubts that pages of cricket history may yet be shredded, the overwhelming likelihood is that Dale Steyn, Vernon Philander and Morne Morkel will ensure that Amla and De Villiers will be able to frame the scorecard and cherish an extraordinary series win.

They should, and will, ensure Faf du Plessis’s autograph is on it, too.