Cape Town – Highly experienced, yet scarily unpredictable fullback Willie le Roux looks like presenting Springbok coach Rassie Erasmus with his biggest selection headache for next Sunday’s World Cup semi-final against Wales at Yokohama (11:00 SA time).

Thirty-year-old Le Roux would earn his 60th Test cap and -- no less crucially -- fifth sampling of RWC knockout-pressure demands if he cracks the nod against the defending Six Nations champions; just the sort of stats that make you an appealing presence for such an occasion, at least on paper.

But his performance across three starts at RWC 2019 thus far has been desperately inconsistent … a hallmark that seriously infected his game in Sunday’s comfortable but imperfect 26-3 quarter-final triumph over gallant, though eventually outgunned underdogs Japan.

Unless injuries intervene in the interim, Erasmus shouldn’t have too many head-scratchers for the Wales showdown; he has a settled fulcrum of a “first team” and won’t wish for major deviation at this advanced stage.

Le Roux, however, is undoubtedly cause for concern form-wise.

After a bright showing in the more clear-cut, pre-tournament 41-7 disposal of the Brave Blossoms in Saitama, the No 15 has mixed the good with the rank bad, during the tournament itself, in a berth where there is a higher premium than many others on “certainty”, if you like.

The player is capable of sublime moves in the blink of an eyelid, but the successive matches he’s begun against New Zealand (23-13 loss), Italy (49-3 win) and now the quarter-final at RWC 2019 have also seen him make quite glaring errors with undesirable frequency.

That is no special comfort to Bok enthusiasts … and will be picked up on, you can be sure, by Warren Gatland and the other Welsh masterminds ahead of the semi.

Wales are a team renowned for keeping the ball in play as much as possible.

Outspoken, much-travelled guru and former Springbok centre Brendan Venter raised the stakes even higher, really, in a tweet (@BrendanVenter) after the Bok quarter-final in which he warned: “Wales will attack our backfield with an aerial bombardment.”

Based on his frankly wretched first half in a broad sense against Japan, and with memories of his high-ball frailty against the All Blacks in the pool opener still fairly vivid as well, is Le Roux the right medicine for fullback retention under such circumstances?

That will be something for Erasmus to mull over in some depth over the next few days.

Le Roux’s bravery should not be called into question: he had two pretty violent knocks relatively early in Sunday’s game, once when team-mate Pieter-Steph du Toit came clattering into a breakdown and his legs made contact accidentally with

the fullback’s head at some pace, and also a painful landing after a contest with Japan loose-forward strongman Michael Leitch in the air.

But the fact remained that his catching was too often “hit or miss”, his passing inexplicably inaccurate at times, too, and there was one spillage under no special pressure of a pass as the Boks looked to launch a rare ball-in-hand backline raid.

On the more positive side, Le Roux may yet be saved, selection-wise against Wales, by having fallen in line to some degree after halftime with the collective improvement of the Bok team, as they finally showed greater composure and turned screws clinically.

Still, debate will rage early in the week around possible better options in the last line of defence against the men in scarlet jerseys, who also blew decidedly hot and cold in pipping France in their quarter-final.

The situation may be complicated by tenacious little wing Cheslin Kolbe taking further physical punishment – he had been battling with an ankle problem ahead of the Japan clash – in the match; he had looked more assured under the aerial ball and has very sound No 15 credentials of his own.

While it is difficult to envisage Erasmus suddenly opting for the only nine-cap (including four fullback starts) Warrick Gelant for such a high-pressure encounter, versatile, broad-shouldered and enormously street-wise Frans Steyn wouldn’t be the worst call for the berth – especially with his renowned ability to hoof the ball back the proverbial mile when required to do so.

Steyn has largely been an impact substitute for the Boks in bigger matches at the tournament, but he sports 14 prior fullback appearances in green and gold, including some stellar showings in the spot during 2009, when South Africa won both the British and Irish Lions series and later the former Tri-Nations.

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