How much can change in the space of three years? The respective fates of the Irish and South African rugby teams over the past 36 months offer a timely reminder.
ack in 2017, remember, there was little debate about which was more likely to win the World Cup in Japan 24 months later.
When the two sides met that November in what remains the last clash between the nations drawn yesterday to face each other at the 2023 World Cup, the gulf in both class and confidence was apparent.
What was then Joe Schmidt's side humbled the mighty Springboks, a 38-3 victory in the Aviva Stadium coming courtesy of four tries, with only an Elton Jantjies penalty early in the second-half preventing the visitors suffering the indignity of being nilled.
While three of Ireland's scores came late in the piece, the scoreline was no unfair reflection of the direction of traffic, nor of the two sides' apparent trajectories as Japan came into view.
With the pair already fated in the minds of fans and journalists alike to be on course for a quarter-final meeting out in the Land of the Rising Sun, Ireland looked short odds to finally shake that semi-final-shaped monkey from their collective back, a prevailing opinion only strengthened when the Irish carried the momentum of that day through into an unforgettable 2018 that featured a Grand Slam and the beating of the All Blacks in Dublin.
There is little meat left on the bone of what happened next but a quick refresher nonetheless.
Rassie Erasmus, who had won the PRO12's coach of the year when at Munster, took office as South Africa's Director of Rugby in early 2018, quickly sacked coach Allister Coetzee and took on the hotseat himself.
A restorative win over the All Blacks followed later that year as well as the Rugby Championship crown in 2019.
And all that before the sight of Siya Kolisi hoisting aloft the Webb Ellis into the Yokohama night sky became one of World Cup history's enduring images.
They hadn't met Ireland in that projected quarter-final, of course. By then the wheels had spectacularly come off the Irish charge, a chastening 2019 Six Nations preceding a tournament in which the shock loss to Japan set up a thumping at the hands of the All Blacks instead.
So, while it is already tempting to map out Ireland's 2023 World Cup, where they were paired with Scotland too in a repeat of the 2019 pool stages, these past three years should offer a reminder that judgement should be withheld until much, much, closer to the time.
Which, at least, will come as a relief to Ireland.
While South Africa have been idle since that World Cup win thanks to the effects of the coronavirus on their schedule - indeed, they would have been back in Dublin last month under original plans but should still make that trip in either the next two autumns - Ireland's hangover from the tournament has lingered.
The problems posed by the most physical of opposition, a tag which certainly applies to the Springboks, persists, while the blooding of 11 new caps by new head coach Andy Farrell has come against a backdrop of largely indifferent performances.
As they face up to the prospect of a pool meeting with South Africa and, should they progress to the knock-outs, a quarter-final against New Zealand or hosts France, it will be them hoping for a similar reversal of fortunes as to that recently enjoyed by the current champions. That much will change off the field is a virtual pre-requisite. At present, when South Africa next take the field it will be in preparation for the visit of the British and Irish Lions.
While all such plans remain dependent on the curtailing of the pandemic in the weeks and months ahead, that prospective first look for the Irish and Scottish tourists will be far from the last.
A trip to Murrayfield in November 2021 has already been confirmed for Jacques Nienaber's side and through the next two autumns they'll have plenty of opportunity to get to grips with northern hemisphere opposition.
Looming on the horizon too, of course, is the switch to a proposed PRO16 by four of their franchise teams.
Whether it be, as expected, the Lions, Stormers, Sharks and Bulls who make the move north, or Ruan Pienaar's Cheetahs which keep their place, those that are set to be central to the cast of characters which will determine Pool B in France will be well acquainted with each other by the time those games finally roll around.
This added element is just one stream flowing into the river's worth of water that will pass under the bridge between now and the tournament.
Few have more recent experience than Ireland and South Africa of just how much the landscape can shift under one's feet during the cycle.
