After three tepid games against under-strength opposition this was the real deal for the tourists who were taking on opponents boasting 16 World Cup winners in their match-day squad.
The so-called second string Springboks won thanks to a ferociously impressive first-half performance which combined supreme physical strength with some brilliant back play.
It was the wingers, Cheslin Kolbe and S’bu Nkosi, who produced a couple of memorable moments to inflict upon the Lions their first defeat of the tour.
Warren Gatland’s side tried manfully to find a way back in the second half but Wyn Jones’ try was not enough.
All the talk pre-match had been about the Lazarus-like return of Alun Wyn-Jones. The Lions captain will rejoin the squad on Thursday after taking only 18 days to recover from a dislocated shoulder sustained against Japan in Edinburgh.
But credit is due too to the Springboks for a comeback of a different kind.
They have played just once since lifting the World Cup in Japan 20 months ago but their A team started this match like they’d never been away.
Call it muscle memory, perhaps, but there was certainly no lack of aggression as Liam Williams found to his cost when he was clattered in the opening seconds.
The Welsh full-back was a late replacement for Josh Adams who was given leave of absence to join his partner via Zoom to witness the birth of their first child.
If that was a rude awakening, there was plenty more to come.
Owen Farrell, another late replacement after Dan Biggar sprained his ankle in training, was struggling to come to terms with the pace of the game.
South Africa A were ruling the roost and only Anthony Watson’s brilliant last-gasp tackle denied Nkosi an early try.
Play went back for a penalty due to an earlier infringement and veteran stand-off Morne Steyn put the hosts ahead.
Nkosi was not to be denied for long and the Lions had no answer to his electric pace.
Farrell, under pressure, had his kick charged down by Eben Etzebeth deep in the South African half. Damian de Allende, the centre, gathered before passing to the winger. Nkosi did the rest, streaking clear before stepping inside Louis Rees-Zammit’s valiant attempt to stop him. It was a wonderful try and de Allende deserves credit for matching Farrell stride for stride as the fly-half tried to atone.
Steyn’s conversion had the home team 10-0 ahead and the Lions were wondering what had hit them. The tourists had averaged 60 points per game in their three previous tour matches but that was against provincial makeweights deprived of their internationals. This was a different level.
Farrell reduced the lead with a penalty and there were more shoots of recovery from the Lions thanks to an encouraging burst from Tom Curry.
But the revival was short-lived. South Africa A increased their lead and it was all down to the brilliance of Kolbe. Taking the ball in his own half, the winger slowed things right down before slaloming between Rees-Zammit and Chris Harris with a dazzling burst of pace. The Lions were all at sea as Kolbe offloaded to Lukhanya Am and the captain finished the move. It was a superb passage of play and Steyn added the extras.
The Lions needed to find a way back and their cause was helped by the hosts being reduced to 13 men. The tourists were finally finding their form and enjoyed a sustained period of pressure. Josh Navidi was denied by some resolute defending but as the play shuffled along the South Africa tryline and Navidi made another incursion, Faf de Klerk clashed heads with the flanker and was shown yellow for failing to use his arms.
He was followed into the sin-bin by Marco van Staden, a repeat offender as the Boks defended desperately.
The Lions thought they had scored a try just before half-time but Wyn Jones was judged to have made a double movement before he touched down.
Given their lack of matches, it was perhaps not surprising that South Africa A tired in the second period but the visitors deserved credit for the way they edged their way back into the game.
Harris, the Scotland centre, sparked a fine counter attack involving Taulupe Faletau and Rees-Zammit and then Anthony Watson tried his luck. But when the try finally came it was all down to front-row grunt. A short tap penalty was passed to Wyn Jones who powered over from close range, hurting his shoulder in the process. The Wales loosehead was replaced by Mako Vunipola as Farrell kicked the conversion.
The England stand-off then added a penalty to reduce the deficit to four points as the Lions sensed the balance was tipping their way.
Rees-Zammit thought he had put the tourists ahead as stretched for the line. He was agonisingly short and when he tried to find the extra inches he was penalised for playing the ball on the floor.
Time was running out for the Lions and Steyn had the chance to increase the Boks’ lead but dragged his long-range penalty wide. The venerable stand-off is 37 and was a mainstay of the South Africa side that played when the Lions last came calling, in 2009. He was clearly loving being back in the spotlight and tried his luck with a drop goal attempt which missed the target.
Scorers: South Africa A: Tries: Nkosi, Am. Cons: Steyn 2. Pen: Steyn
British & Irish Lions: Try: W Jones. Con: Farrell Pen: Farrell 2.
South Africa A: le Roux (Kriel 55); Kolbe, Am, de Allende, Nkosi; Steyn, de Klerk; Kitshoff (Oosthuizen 62), Dweba (Marx 38), Nyakane (Koch 40), Etzebeth, Mostert, van Staden (Van Rensburg 64), du Toit, Wiese.
Replacements: Elstadt, H. Jantjies, Willemse.
British & Irish Lions: Williams (Daly 12); Rees-Zammit, Harris, Aki, A. Watson; Farrell, Murray (Davies 76); W. Jones (Vunipola 45), Owens (Cowan-Dickie 51), Sinckler (Fagerson 62), Itoje, Henderson (Beard 62), Navidi (Beirne 69), Curry, Faletau (Simmonds 47).
Referee: Jaco Peyper (South Africa)