Australia begin their 14th Test since the start of the pandemic on Friday, aiming to take a 2-0 series victory over Sri Lanka in Galle.

In that time since March 2020, Warner has not scored a single century and Smith has reached triple figures just once.

Despite that, Australia have still climbed to the top of the ICC rankings and sit clear first in the World Test Championship.

It's a situation that would have seemed unimaginable between the start the 2013-14 summer and the ball-tampering scandal in 2018.

Back then, the pair made 35 per cent of Australia's runs and scored 40 of the team's 75 hundreds.

Illustrating their dominance, Smith scored 5434 runs in that period, Warner 4962 and Usman Khawaja was next best with 1789.

When the pair were out after Cape Town, Australia won just two of eight Tests without them and went a home series against India without a century.

But the seeds of struggle have now begun to bear fruit.

During the pandemic-era, Warner and Smith have contributed 20.1 per cent of the runs but Australia's average score has remained around the same.

Marnus Labuschagne has been Australia's best, while Travis Head was man-of-the-series in the Ashes after both debuted in the struggles of 2018.

"The thing is they (Warner and Smith) have still been batting well around that," coach Andrew McDonald told AAP.

"Whilst people talk about the key milestone which is the hundreds, they've still batted well and made scores.

"I am excited by how it will look when they get into what their own individual expectations are, which is scoring hundreds and big hundreds.

"Travis Head has been outstanding with the growth there. Cameron Green is developing and Uzy has been outstanding as well on his reinclusion."

Smith spoke last month of his desire to bat under pressure again, after shooting out of the blocks on his return in the 2019 Ashes.

But he has maintained the century drought has not played on his mind, albeit conceding he had erred on the side of being too defensive in recent years.

The right-hander has hit 739 at 39.45 during COVID to sit third on Australia's run-scoring charts, passing 50 more than any other player.

Warner sits fifth with 544 runs at 30.22, with his last ton coming back in January 2020.

AUSTRALIA'S SMITH AND WARNER RELIANCE

NOVEMBER 2013 - MARCH 2018

* Combined runs: 10,396 of Australia's 29,688 (35 per cent)

* Centuries: 40 of 75 (53 per cent)

* Team average: 38.30 runs per wicket

* Overall record: 30-6-16

MARCH 2020 - CURRENT

* Combined runs: 1333 of Australia's 6607 (20 per cent)

* Centuries: 1 of 9 (11 per cent)

* Team average: 35.71 runs per wicket

* Overall record: 7-4-2

Australian Associated Press