South Africa 421 (de Villiers 148) & 124-2 beat
West Indies 329 & 215 by eight wickets
Third Test, Cape Town
Dean Elgar's unbeaten 60 guided South Africa to an eight-wicket win over the West Indies on the final day of the third and final Test, wrapping up a 2-0 series win.
The Proteas needed 115 runs to seal victory on the final day and despite a slow start, they made it comfortably.
Du Plessis fell when he edged Sulieman Benn to Devon Smith before Elgar and Amla added an unbroken stand worth 73 to add a convincing win in Cape Town to the innings victory at Centurion.
That also confirmed that they will end the qualifying period later this year as the world's number one-ranked Test side, and they were presented with the symbolic mace - and a cheque for $US 500,000 - at the end of the game.
It took them a while to get going, however, and the West Indies were able to keep it tight early on and prevent runs flowing freely.
However, once du Plessis had got off the mark - and edged a couple of fours along the way - and Elgar found his touch, the eventual outcome of the game was never in doubt.
And while Benn bowled tidily from one end, returning figures of two for 24 in 17 overs, there wasn't quite as much control at the other end.
Elgar struck seven fours and a six, including some authoritative pull shots and one booming maximum straighth down the ground.
Du Plessis lost his wicket when one turned and bounced sharply at him, caught the shoulder of his bat and flew up into the air for Smith to take a comfortable catch.
Amla then batted fluently, hitting six fours to ensure that the match didn't even get to lunch on the final day.
AB de Villiers was named as the man of the match after his 148 set up South Africa's first innings of 421 while Dale Steyn and Simon Harmer both took seven wickets in the game as the West Indies were bowled out for 329 and 215.
© Cricket World 2015