Rossouw and Amla tons set up 4-1 series
South Africa 361 for 5 (Amla 133, Rossouw 132) beat West Indies 230 (Samuels 50, Parnell 4-42) by 131 runs
Scorecard and ball-by-ball details
A performance of all-round quality to match their huge win at the Wanderers ensured South Africa ended their season on a high with a 131-run win in Centurion in their final international before the World Cup. Rilee Rossouw's 83-ball hundred provided him the highest peak of an undulating start at ODI level and he joined forces with the peerless Hashim Amla, who played with rare abandon during his occasionally brutal 133, as the pair added a record 247 for the third wicket.
South Africa piled up a gargantuan 361 for 5 and the carnage in the second half of the innings brought back memories of the Wanderers as West Indies' bowlers were flayed, powerless to stop the onslaught. At the 20-over mark the score was 105 for 2, a modest run-rate of just over five-an-over, but the last 22 overs of the innings brought 256. The innings concluded in a fitting manner as JP Duminy smote a straight six, the 17th of the innings. A full innings, and 439 would have been threatened.
Chris Gayle's miserable series then concluded with a first-ball duck and though West Indies flung the bat the effect was never going to be enough. Wayne Parnell, one of South Africa's squad bowlers who could yet make-or-break the World Cup campaign if injuries come along, then earned himself a valuable confidence boost with 4 for 42 during a spell of eye-catching pace. As evidence around the world is showing, a left-arm quick can be priceless.
Still, Parnell is likely to start the World Cup as a reserve. It will be fascinating to see if the same is true of Rossouw after a series including two hundreds. He would probably like to play all his cricket on the Highveld and his second ODI ton followed the one he made in Johannesburg which was subsequently overshadowed by AB de Villiers' record-breaking hundred. Then he was opening, this time he was No. 4 after a reshuffle of the order to accommodate the returning Amla - who had been rested for the Port Elizabeth match - and the fit-again Quinton de Kock.
He came to the crease in the tenth over and initially took his time to get going as he moved to 25 off 42 balls before collecting his first six off Narsingh Deonarine. He then quickly started playing catch-up, reaching fifty off 60 balls before helping himself to 23 off Andre Russell's sixth over. His pulling stood out as he repeatedly flicked balls off his hip from a regular supply of short deliveries, but there was also a fair smattering of stinging straight drives as he batted with a freedom that he has rarely shown early in his career.
Understandably, he slowed a little as three figures approached, taking 11 balls to go through the 90s, but his hundred came with a brace to deep midwicket and he was soon unleashing again as he took two fours and two sixes off the 37th over bowled by Jason Holder.
The game, meanwhile, was running out of superlatives to describe Amla's batting. This was his fourth innings of the series and he has not failed to pass 61. By the time he fell in the 41st over his series tally stood at 413 runs at 206.05 - his other dismissal being a run-out in Durban - the most runs for a South Africa batsman in a bilateral series (overtaking his own record of 402 against West Indies in 2010).
After the early loss of de Kock - who top-edged to point when beaten for pace and bounce - on his return from an ankle injury, Amla was soon ticking along at a run-a-ball or better as he feasted on bowling that was soon either too full or too short and wasted helpful conditions.
Amla's early momentum helped Rossouw settle but he was also content to sit back and watch his young team-mate cut loose first before using his experience expertly to ease the pressure of him as three figures approached by taking charge of dispatching the bowlers. Three sixes came in seven balls against Sheldon Cottrell and Darren Sammy; all of a sudden it looked as though he may beat Rossouw to three figures.
In the end he was the second man there, from 92 balls, and what followed was a destructive display of batsmanship that is not readily associated with someone like Amla whose trademark is steady accumulation. Alongside the avalanche of fours there was an extraordinary one-handed six over third man as he stretched to reach a wide delivery from Russell.
West Indies' innings began in curious a fashion, and a disappointing one for those hoping for a close a match although Gayle's ODI record in the last two years does not suggest a rollicking hundred was an imminent prospect. This time he reached for a wide delivery first ball, the South Africans went up in appeal but the ball was called wide. Amla reviewed and Snicko showed a toe-end from Gayle as he ended with 71 runs at 14.20.
Although Deonarine and Dwayne Smith played their shots, taking early toll on Kyle Abbott and Marchant de Lange, who had been called in from the South Africa A squad, the pressure of the target was always going to be too great. Aaron Phangiso produced a lovely delivery to remove Smith and then Marlon Samuels was involved in his fourth run out of the series to send Deonarine back.
Samuels and Denesh Ramdin added 91 in 13 overs to at least keep South Africa's second-string attack on their toes. It was Parnell who gained most when wickets started to tumble, the most eye-catching delivery being the short ball which climbed at Ramdin and was fended away to midwicket.
After claiming two more in four balls in his seventh over he should have completed his five-wicket haul, but Duminy spilled a chance at deep square leg much to the bowler's annoyance, although he soon found a smile and even received a consoling pat on the back from Sammy. After another crushing defeat, though, it was really West Indies who needed the consoling.
Andrew McGlashan is a senior assistant editor at ESPNcricinfo