"It was the right time to go, considering there are three or four younger players who could come in for the next WTC cycle," Karunaratne told ESPNcricinfo. "Plus, this match was in Galle, where I made my debut, so it will be nice to finish things there.

"After the first Test against Australia ended, I told SLC that the next Test would be my last."

Karunaratne had made his Test debut in November 2012 against New Zealand, at the same ground where he is now set to retire. He was dropped from the team briefly in 2014, but struck his first Test hundred towards the end of that year. He has hit 15 centuries since, more or less enjoying a consistent place in the Test team, until becoming one of its senior-most players.

Through the course of his 12 years in Tests, Karunaratne has scored by far the most Test runs for a Sri Lanka opener, hitting 7079 at an average of 39.99 in that position. He will also become Sri Lanka's seventh cricketer to 100 Tests, following Sanath Jayasuriya, Muthiah Muralidaran, Chaminda Vaas, Mahela Jayawardene, Kumar Sangakkara and Angelo Mathews.

"Playing 100 Tests is a tough thing to accomplish, especially when you're an opening batter and you're doing the dirty work for the team," Karunaratne told ESPNcricinfo. "If I have regrets, one of them would be not being able to get to 10,000 Test runs. I thought the way that I was going in 2017, 2018 and 2019, that I'd have the chance to get there. But then Covid hit, and Sri Lanka don't play as many Tests anymore.

"I'll take a bit of a break for myself after spending so many years playing cricket. But eventually, I'd like to get involved again"

"I'd also have loved to make it to a World Test Championship final and experience that feeling of being in a final. We were close twice, but it never happened."

Now based in Melbourne, Karunaratne hopes to pursue coaching after his retirement. "I'll take a bit of a break for myself after spending so many years playing cricket," he said. "But eventually, I'd like to get involved again."

The second Test against Australia - now Karunaratne's last - begins on Thursday.