South Africa 384 for 6 (Amla 154, de Kock 109) beat Sri Lanka 296 for 8 (Gunaratne 114*, Pathirana 56, Morris 4-31) by 88 runs
Scorecard and ball-by-ball details

South Africa rode a roaring 187-run first-wicket stand and two effortless centuries from their openers to a monumental 384 for 6 and, eventually, the No. 1 ODI ranking. Their reward for winning an 11th ODI on the trot was the unseating of Australia - whom they had also thrashed 5-0 at home last year - and moving one point clear at the top of the table.

South Africa's dominance of Sri Lanka in this series has been complete. They outbatted, outbowled and outfielded the visitors again, and this win - an 88-run thumping - was a fitting finish. The only consolations for Sri Lanka were Asela Gunaratne's hard-earned-but-inconsequential maiden century, as well as having batted 50 overs for the first time in the series.

If Quinton de Kock was the early aggressor, taking the innings by the collar inside the Powerplay, Hashim Amla bided his time, and only later fashioned violence from timing and grace. Amla embraced all-out attack only after reaching triple figures, but even at his most belligerent, did not lose the characteristic zen. The head stayed steady and the wrists whipped through the ball at the point of contact. His 154 from 134 deliveries was his second-highest ODI score, and again helped showcase the awesome might of this South Africa top order. Even on days when AB de Villiers does not fire, they can still make insurmountable scores.

It was thanks to more poor catching, more wayward bowling, and the general lack of menace in their attack that Sri Lanka found themselves stuck chasing the biggest score of the series. Though they had made something of the pursuit of 368 in Cape Town on Tuesday, they did not manage to stay in the game beyond the early stages of their innings this time.

Niroshan Dickwella flashed attractively for a 19-ball 39, but the rest of the top order fell around him. They were 82 for 5 in the 14th over, their fate virtually sealed, but Gunaratne and Sachith Pathirana sought to make the best of a bad situation by putting on a 93-run sixth-wicket stand. After Pathirana departed, the tail made it their mission to get Gunaratne to his hundred. He wound up with 114 off 117 balls, and Sri Lanka made their way to a somewhat respectable 296 for 8.

Sri Lanka had in fact asked South Africa to bat at the toss, and though Suranga Lakmal bothered Amla's outside edge in the early overs, de Kock quickly set about lighting the thrusters under the innings. He collared a pair of boundaries in each of the eighth, ninth and tenth overs. By the time the fielding restrictions ended, South Africa had sped to 71 for no loss, and de Kock to 47 from 35 balls.

When slip fielder Upul Tharanga failed to lay a hand on a catchable outside edge from Amla in the 15th over, South Africa were allowed to continue progressing at their hectic pace.

Tharanga did change his bowlers up regularly, in attempts to prevent batsmen from establishing a rhythm, but save for that edge from the offspin of Dhananjaya de Silva, chances failed to come. Both batsmen were severe on errors of line from the spinners, who collectively bowled quickly through the air. With little turn on offer, de Kock and Amla were plundering runs into the outfield off most deliveries, and rarely failing to seize boundary opportunities.

At the halfway stage of the innings, no bowler had managed to concede less than a run a ball and South Africa, at 180 for 0, were almost certainly heading for a mammoth score. It was in the 25th over that de Kock struck his 15th four of the innings - a powerful sweep to beat backward square leg - and went to triple figures for the 12th time in his ODI career. Few of his other hundreds would have come so easily. He holed out to deep cover soon after, though, finishing with 109 off 87 deliveries.

Perhaps in an innings like this, it is the likes of de Villiers, JP Duminy and Farhaan Behardien who are expected to take control of the death overs, but in fact it was Amla himself who led the final charge. Having timed the ball beautifully for the first 40 overs, he seamlessly incorporated power into his game after completing his 24th hundred in the 41st.

He carved sixes over point, slammed the short balls over deep square leg, and even struck cleanly down the ground - launching successive Lahiru Madushanka balls over the rope between long-on and cow corner in the 47th over. Having scored his hundred at slower than a run-a-ball, Amla smoked his next 54 runs in 22 deliveries. Each of his five sixes came in that period.

Sri Lanka's top order came out attempting to get ahead of their taxing required rate early, but wound up making too many fatal mistakes. Tharanga sent an outside edge to third man in the fourth over; Kusal Mendis picked out mid-off with a lofted drive in the sixth; Dickwella, after slapping and scooping merrily, was caught at mid-off as well. Sandun Weerakkody and de Silva did not last long either - the latter's modest tour of South Africa ended by a Tahir googly, which bowled him through the gate.

Gunaratne was slow to begin with but sped up after the departure of Pathirana, who had been the aggressor in their association. Having seen off the quicks, Gunaratne picked out the spinners to attack, sweeping and reverse-sweeping especially well, while the likes of Jeffrey Vandersay and Lakmal gave him company. He reached triple-figures in the 48th over - his second fifty having come off 25 balls.

Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @andrewffernando