Watch all 10 Australian wickets to fall

Australia’s humbling at the hands of an unfancied but irrepressible young Sri Lanka was completed in less than three hours of fragile batting in a manner that was difficult to reconcile but at the same time utterly predictable.

Set an unlikely 324 to salvage the final Test in a series already lost, the Australians again had no answer and as few clues against the left-arm spin of 38-year-old Rangana Herath who finished today on one leg, but with a spring in his step and 7-64 in his pocket.

With the final margin a hefty 163 runs.

Raw vision: Sri Lanka's players celebrate in Colombo

The encouraging signs that Australia showed in the first three-and-a-half days of this dead-rubber Test were swept away in a panic-ridden collapse in which the last nine wickets fell for 60 runs in barely 21 overs to once again highlight the team’s huge fallibility against quality spin bowling.

In spin-friendly Asian conditions where Australia has now posted just one win from their past 18 Tests, stretching back almost eight years.

Quick Single: Australia dethroned as world no.1

The loss of the world number one ranking should be seen as but a blip in the review of this campaign that will surely rank as one of the most embarrassing and perplexing of recent times.

Australia collapse against Sri Lanka's spin

Even for a team, such as the one Steve Smith led here with such high expectations, that remains in the midst of a significant rebuilding of personnel.

Sri Lanka’s decision to bat into the fifth morning, despite a paucity of time in which to bowl out the Australians looming as the only logical impediment to them completing an historic series clean sweep, sent a clear message.

And one that was amplified by the Australians who, seeing the prospects of a draw looming ever larger with each futile minute, dawdled through an alarmingly pitiful four overs in the first half hour.

Which meant the hundreds of punters spending their Buddhist Poya Day public holiday queuing in the broiling morning heat along adjacent Maitland Place for a berth at the solitary ticket window missed little other than a shower of boundaries from first innings century maker Dhananjaya de Silva.

And Mitchell Starc being catered and fitted for a new pair of shoes, not surprising given he bowled almost three times as many overs (103.2) than the combined output of Sri Lanka’s seamers across the series, and fought a running battle with the SSC’s disappearing crease line throughout the final match.

But when Starc inadvertently let loose a shoulder-high beamer at De Silva midway through the morning’s fifth over and offered an apology while blaming the crumbling footholds for the misadventure, Mathews called a halt.

Starc's radar off target as Sri Lanka declare

To salvage something from a series already well lost, the Australians needed to produce their highest fourth innings total in a Test match since their failed chase at The Oval seven years earlier.

And a final innings pursuit larger than any previous Australia team has managed in Asia.

The intent so blatantly absent with the ball suddenly manifested with that bat, as Warner and Shaun Marsh set about the unlikely target at the required rate of around four runs per over.

Warner was abetted by off-spinner De Silva re-gifting the present he offered up to the Australia opener with his opening delivery of the first innings – a knee-high full-toss that Warner accepted by belting it into the slowly growing crowd at mid-wicket.

Australia’s cause looked to have been helped when Mathews burned both of his team’s reviews in consecutive balls trying to have a declined appeal for a catch at slip (off the pad) and then another for lbw (pitching outside leg) overturned.

But that fortune lasted just a few more overs when, within touching distance of lunch, Marsh gloved a ball from Dilruwan Perera that jumped off a length and flew shoulder-high to Kusal Mendis at short leg who parried it and then grabbed the chance at the second attempt as he tumbled to the ground.

SL burn both reviews, but claim brilliant catch

The first sizeable stone in Australia’s defence had been dislodged, and when the second fell 16 minutes later the whole façade began to crumble with alarming (if not unexpected) speed.

And there has been few more illustrative examples of this campaign’s failings than the manner in which Smith fell just 14 balls into the innings that was expected to determine the outcome of this match.

In identical fashion to the way he was knocked over in Australia’s humbling first innings at Galle, Smith rocked back to cut Herath whose not-so-secret weapon has been the flatter, faster ball that hurries on with the arm.

Unfortunately for Smith, the only Australia batsman in the series to twice reach 50 in these three Tests, he had failed to identify the one that was flatter, faster and that hurried on with the arm – fizzing past the under edge and crashing into the exposed stumps.

It was the fifth time in six innings the 38-year-old spinner had owned the world’s number one Test batsman, with all five of those dismissals the result of bat missing ball – a pair of stumpings, clean bowled a couple of times and an lbw thrown in for variety.

Watch all 28 of Rangana Herath's wickets

And from there, just as the tourists had identified in their exhaustive pre-campaign planning, the subcontinental succumbing gathered breakneck speed.

Smith’s departure triggered the sort of collapse not seen since the previous Test a week earlier in Galle, with five wickets dissolving for the addition of 23 unconvincing runs from 39 deliveries that might as well have been rocket-propelled grenades fired into the dusty pitch.

But much of the carnage visited upon Australia’s shell shocked batters was, as had been the case more often than not through this campaign, self-inflicted.

Adam Voges again played for Hearth’s phantom spin in the same over that Smith fell, while Warner thought that Dilruwan Perera pitching routinely outside leg stump meant he didn’t have to offer a shot only to find that the ball can find the stumps from that trajectory if left unimpeded.

Moises Henriques' return to Test cricket three years in the making ended with a net deficit of one run, the eight he scored with the bat in two innings cancelled out by the nine runs he conceded from the couple of overs he was asked to bowl.

However, the allrounder can consider himself stiff given the eccentric manner of his demise, advancing down the pitch only to deflect the ball to slip from where it was pitched on to the stumps as he thrust his bat in beseeching search for the crease line.

Henriques is caught short by Angelo Mathews // Getty

Not the first participant in this Test to have undertaken that mission, with the nominal white line regularly lost in the crumbling earth at either end of the pitch.

Little wonder Henriques was unable to prove that some portion of his bat was behind the crease when it acted like a blunt-nosed shovel pushing chalk, dirt and detritus with it as it slid in search of safety.

Likewise his fellow allrounder Mitchell Marsh, up until today the only Australia batsman to reach double figures in every innings, who again looked as comfortable as anyone in stroking a pair of boundaries before he copped a peach from Herath that would have accounted for many a more credentialled batter.

If they weren’t all watching on in abject misery from the dressing room.

Once Peter Nevill fell for two, completing a series in which he enhanced his reputation as a keeper but left significant questions over his batting capabilities, the only sense of battle left in the Test was the duel between Herath and Starc to decide the series’ leading wicket-taker.

As heroic as Starc has been throughout in single-handedly keeping Australia in matches their poor batting would end up losing, Herath deserved to claim the crown.

Watch all of Starc's 24 wickets v Sri Lanka

Limping noticeably, still feeling the effects of a sickening blow to the groin when batting last Sunday, unsure of his place in the team at the series start and his future now that it’s ended, he fittingly became the bowler of the tour when he had Starc caught at square leg.

Quick Single: Starc's stunning series by the numbers

Which sounds straightforward until it’s revealed the catch was taken from a skied mishit, with the catcher being stand-in keeper Kusal Perera, who covered the ground like a wind-assisted Usain Bolt such was the adrenaline coursing through the euphoric Sri Lankans.

Another line-ball stumping to remove Josh Hazlewood in his next over gave Herath 12 wickets for the match – the most by a Sri Lankan in a Test against Australia, eclipsing their greatest ever bowler Muthiah Muralidaran – and then the SSC began vocally willing him on to a 13th.

Which arrived at the start of his 19th over when Nathan Lyon missed a sweep shot, the theatre of the moment scarcely dimmed by the Australian’s perfunctory call for the decision to be reviewed.

The futility of which was shown by the fact Sri Lanka’s players had already souvenired most of the stumps before huddling together in a celebratory ring and then being cheered and serenaded to the boundary like conquering heroes.

Which in national folklore they will forever remain.