Dinesh Chandimal's career looked close to over when he last played a Test series against Australia but the batsman has landed a knockout blow in Galle.

The last time Dinesh Chandimal played a Test series against Australia he was captain of a sinking ship and about to be thrown off without a life jacket.

Struggling for form and leading a team in crisis, Chandimal scored just 24 runs across four innings in 2018-19 and didn't pass 15 in an innings.

When Sri Lanka's players boarded a flight for South Africa and their next Test series days after the final match in Canberra, Chandimal was told not to bother.

Instead, placed onto on a different plane back home to Colombo, Chandimal was forced to start again.

On Monday, he did that and more, smashing an unbeaten 209 against Australia in Galle to set up the hosts' innings and 39-run victory.

"I'm over the moon," Chandimal said.

"I just wanted to be proactive against the spinners and at the same time rotate the strike. That's what I did, and finally it worked."

Chandimal's turnaround is emblematic of his career.

He has been dropped countless times, routinely brought in and out of Sri Lanka's team since his debut in 2011.

As recently as last year he considered giving up on Test cricket to play County Cricket after being handed the most recent of his setbacks.

Even in this Test in Galle, the right-hander needed his fair share of persistency.

He could have been out on both 10 and 30, firstly when Alex Carey missed a tough stumping off Nathan Lyon and when Australia's lack of reviews meant an edge went undetected.

But the right-hander fought hard enough to bring up his century off 195 balls on Sunday, doing so when he tapped and ran off Nathan Lyon.

The latest iteration of a more attacking Chandimal was on show on day four.

The 32-year-old began by sweeping Nathan Lyon for boundaries twice early in the morning, giving Sri Lanka the ascendancy and limiting any chance of a close first-innings margin.

Then he rammed home the advantage.

In the space of 10 minutes he three times hit Mitchell Starc back over his head for six, including one that landed on the road behind the ground and almost hit a pedestrian.

Another ball was cut over point for six off Pat Cummins, by far the classiest shot of his 16 boundaries and five sixes.

By the time he ran out of partners he had the highest score by a Sri Lankan against Australia, and the ship had well and truly been steadied.

"I've been in the side, not in the side, but your family and wife is always there," Chandimal said.

"I also want to thank my teammates, who've always been there as well as my support staff and the fans."