Cape Town - Do some of my core personnel have sufficient petrol in the tank for two further Test matches?

That will probably be a question playing on the mind of Springbok head coach Rassie Erasmus as he trains his thoughts on the “final straight” of their European tour - Scotland at Murrayfield on Saturday and then Wales in Cardiff a week later.

Currently sitting with a one-from-two record on tour, following the English loss and now French victory (plus a still tenuous 6/12 win record overall in his tenure), Erasmus has a bit of a catch-22 situation to deal with for game three in Edinburgh.

His primary instincts may very well be that any temptation to “experiment” to a notable degree against the Scots is fraught with too much peril.

Gone are the days that any of the formerly Five Nations teams can genuinely be called easy prey for southern giants like the Boks or All Blacks: or put it this way, foes against whom you can feasibly take the risk of putting out something nearer a second string against them.

Scotland have cranked up a notch to sixth on the World Rugby rankings after the latest round of November internationals; they were also third-placed finishers in this year’s Six Nations, ending a spot above the French team dramatically subdued by the Boks in the 85^th minute in Paris at the weekend.

Yet the dilemma Erasmus has is that certain of his frontline players - and especially one or two in the pack - are showing some signs of year-end fatigue, both physically and mentally.

That continued in certain cases against France, where captain Siya Kolisi and loosehead prop Steven Kitshoff - just as immediate, admittedly debatable examples - looked like candidates for a bit of “rotation” in their specific positions.

Kitshoff was solid enough in the limited scrummaging opportunities on the night, but he has just shed some of his effectiveness as a ball-carrier and crunching tackler in recent weeks, while open-side flanker Kolisi has arguably fallen even more off his normally zesty A-game.

He just seemed subdued both in a leadership and playing capacity at Stade de France, not managing to make any special impression at the breakdown or on the drive, and lacking his traditional penchant for at least one thrilling, fairly long-range charge and link-up in open play.

Another staple green-and-gold customer this year who is admittedly not showing it yet, but may be perilously close to a “running on empty” phenomenon, is versatile forward Pieter-Steph du Toit.

It has almost become par for the course for Du Toit, whether employed at lock or blindside flank, to top the Bok tackle count – he apparently did so again in Paris, including some real bone-crushers - and that must take a mounting toll on the body.

For the Boks to be deemed to have had a successful northern-climes trek in the results column, Erasmus knows only too well that both of the next two games, ideally, need to be winkled out for a 75 percent tour record rather than humdrum 50 percent (or, perish the thought, even less) outcome.

Can he risk resting - or perhaps confining to the substitutes this week - certain of the players mentioned, and perhaps others, in order to recharge them a bit for a big final push against Wales?

That last game will be important not just because it brings down the curtain on the 2018 Bok campaign, and might thus be a game that sits especially vividly in the minds of many supporters during the local off-season, but because the Boks are so overdue to get one over the Welsh.

The men in scarlet have won all of the last three bilateral Tests and four of the last five - and that after a period where the Boks had ruled the roost in as many as 16 prior clashes in a row.

So that has to be a “throw the kitchen sink” game for South Africa, even as they must first find the correct brew, and suitable mental fortitude, to suppress the ever-feisty Scots in their own den.

The Boks need to seriously consider strategically reshaping their starting XV anyway for this weekend, considering how a plethora of key adjustments (either positionally or through use of subs) made a vital second-half difference to their heart-stopping win in Paris after a tepid - at best, frankly - first period.

But at least some of the planning might also need to make provision for a spot of rotational downtime this weekend for overworked figures during 2018 like Kolisi and Kitshoff, something that could pay dividends in revitalising them for the Wales tour-closer.

It is not as though the travelling party is lacking in suitable alternatives: seasoned, Bath-based Francois Louw was a revelation off the splinters in the critical last quarter against France, and could fill Kolisi’s No 6 jersey with aplomb.

Acting leadership would not be a special snag, either, if Kolisi had a well-warranted sit-out at Murrayfield, as these Boks are pleasingly loaded with natural, senior captaincy figures.

Meanwhile the loose-head candidates - should Kitshoff temporarily step away from the frontline - would be either of Trevor Nyakane or Thomas du Toit.

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