South Africa got their World Cup campaign back on track with a convincing 46-6 win over Samoa thanks to a hat-trick from JP Pietersen.
A week on from their shock loss to Japan, the Springboks knew that it was win or bust for them, and they came out with intensity from the off.
Samoa led early with two Mike Stanley penalties and were the better team until the fly-half was picked off by Pietersen for a try against the run of play.
That changed the complexion of the game, and the Springboks, led by the infuriatingly brilliant Eben Etzebeth used all their experience to open up a 17-6 half-time lead.
Pietersen's second try early in the second half put the result beyond doubt, and South Africa were helped by Samoa's stubborn decisions to keep taking tough shots at goal when trailing by three scores.
Despite the best efforts of Tim Nanai-Williams, Samoa committed too many errors to really trouble the Boks, and will have to beat Japan in their next game to keep their own quarter-final hopes alive.
Schalk Burger's try just before the hour set South Africa on their way to a bonus point and it came with ten minutes remaining when Schalk Brits came off the bench and was perfectly positioned at the back of a rolling maul to score.
Pietersen completed his hat-trick a minute from time with a score in the corner, before Bryan Habana got in on the act at the death, completing what will be a welcome success for Heyneke Meyer and his much-criticised Dad's Army.
The Springboks now lead Pool B, and despite their loss to Japan, are favourites to emerge top with games against Scotland and the USA to come.
Fourie du Preez was exceptional for them, while skipper Jean de Villiers also excelled, but it was Eben Etzebeth who was the heartbeat of the team, driving his teammates forward and proving a menace in all aspects of the game.
South Africa showed their intent from the start, smashing the Samoan receiver at the kick-off and earning a penalty which Handrè Pollard converted for a 3-0 lead after barely a minute.
The Springboks meant business and a mammoth rolling maul from the restart earned a penalty as they looked in complete control. A huge tackle from TJ Ioane slowed their momentum somewhat, and it was Samoa who started to grow into the game, levelling on eight minutes with the aid of the post through Michael Stanley after Francois Louw had failed to roll away from a ruck.
Pollard then put the restart out on the full, as South Africa showed some signs of nerves, with Samoa earning a penalty from the resulting scrum which Stanley slotted from halfway to give his team the lead.
Samoa looked the better team, with Nanai-Williams causing all sorts of problems with his quick feet, but against the run of play South Africa grabbed the first try. After going through their backs Samoa looked to have a man over, but Stanley's floated pass couldn't clear Pietersen and he plucked it out of the air before racing 50 metres for the try. Pollard pulled his conversion wide but the Springboks led 8-6.
Pollard added three more a couple of minutes later when Samoa were slow to roll away from a ruck and South Africa moved 11-6 in front.
They were able to stretch the lead to eight points on 24 minutes when Zak Taulafo was penalised for a tackle without the ball on Burger, giving Pollard a simple shot from in front of the posts.
Having been on the back foot early, South Africa were starting to come back into it and almost had a second try on the half-hour. A fine break down the blindside from du Preez had Samoa scrambling and some quick hands saw de Villiers cross. Unfortunately for South Africa, the final pass from Willie le Roux came just after he'd put a foot in touch much to Samoa's relief.
The intensity was huge with hits flying in from both sides. Alesana Tuilagi allowed it to boil over at one point, putting in an unnecessary dig on Etzebeth after the lock had earned a turnover by stopping a Samoan maul.
South Africa moved back up the pitch with the penalty and when Joe Tekori strayed offside, Pollard stretched the lead to 17-6 with Stanley off-target with a 60-metre effort to end the half.
The Springboks flew out of the blocks at the start of the second half and almost had a second try after some fantastic interpassing. De Villiers got away on the left and two quick passes from him to Habana, and then onto le Roux saw the full-back in the clear. He chipped over Nanai-Williams but couldn't regather, knocking on two metres short of the line.
They were over five minutes later though, with Pietersen again on the end of it after good work from the forwards. A powerful maul was eventually stopped by the Springboks worked the overlap and spread the ball quickly through le Roux and de Villiers to send Pietersen over for his second. Pollard converted from the touchline and South Africa led 24-6.
Samoa kept fighting, but the game was getting away from them and it didn't help when Stanley pulled a penalty attempt well wide when kicking to the corner would surely have been the better option.
Stanley was off-target with a third straight penalty effort a couple of minutes later with his final kick of the game as Samoa failed to close the gap once more.
Instead it was South Africa who showed their clinical side, stealing a lineout five metres out before Burger had enough power to crash through the tackle of Ole Avei for their third try. Pollard's conversion came back off the post but South Africa were on their way to a big victory.
Samoa were beaten but they then almost scored the try of the game, inevitably created by the sensational Nanai-Williams. Collecting the ball on the right, he outpaced Tendai Mtawarira, chipped over le Roux and collected but his pass to Kahn Fotuali'i, who in turn found Tusi Pisi, was deemed forward.
And South Africa grabbed the bonus point try with ten minutes to go through Brits, the Saracens hooker the beneficiary of some great work by the Springbok pack as they marched towards the line.
There was still time for Habana to notch up his 60th try for the Boks, with the final play of the game, sprinting away in space after a turnover in midfield.
Man of the match: Eben Etzebeth was outstanding, and probably deserves it, but we can't ignore JP Pietersen's hat-trick. Back in the side, he proved his worth and looked back to his best.
Moment of the match: The opening try turned the match on its head. Until that point, Samoa looked the better team but when Mike Stanley tried an optimistic floated pass, JP Pietersen picked it off, and from there the Springboks were on their way.
Villain of the match: The game looked like it might get out of hand when Alesana Tuilagi put in an unnecessary dig on Eben Etzebeth after a maul. It didn't quite boil over though.
Pens: Stanley 2
For South Africa:
Tries: Pietersen 3, Burger, Brits, Habana
Cons: Pollard, Lambie
Pens: Pollard 4
Samoa: 15 Tim Nanai-Williams, 14 Ken Pisi, 13 Paul Perez, 12 Rey Lee-Lo, 11 Alesana Tuilagi, 10 Mike Stanley, 9 Kahn Fotuali'i, 8 Ofisa Treviranus (c), 7 Jack Lam, 6 TJ Ioane, 5 Joe Tekori, 4 Teofilo Paulo, 3 Census Johnston, 2 Motu Matu'u, 1 Zak Taulafo
Replacements: 16 Ole Avei, 17 Viliami Afatia, 18 Anthony Perenise, 19 Faifili Levave, 20 Vavae Tuilagi, 21 Vavao Afemai, 22 Tusi Pisi, 23 George Pisi
South Africa: 15 Willie le Roux, 14 JP Pietersen, 13 Jean de Villiers (c), 12 Damian de Allende, 11 Bryan Habana, 10 Handre Pollard, 9 Fourie du Preez, 8 Duane Vermeulen, 7 Schalk Burger, 6 Francois Louw, 5 Victor Matfield, 4 Eben Etzebeth, 3 Jannie du Plessis, 2 Adriaan Strauss, 1 Tendai Mtawarira
Replacements: 16 Schalk Brits, 17 Trevor Nyakane, 18 Frans Malherbe, 19 Lood de Jager, 20 Siya Kolisi, 21 Ruan Pienaar, 22 Pat Lambie, 23 Jesse Kriel.
Referee: Wayne Barnes (England)
Assistant referees: JP Doyle (England), Angus Gardner (Australia)
TMO: Graham Hughes (England)