Sri Lanka’s win by an innings and 39 runs meant that the two-Test series ended 1-1, with the two sides sharing the Warne-Muralidaran Trophy.
The 1-1 series draw comes after Cummins’ side edged Pakistan away 1-0 in a three-game Test series earlier this year.
Australia had looked far stronger than Sri Lanka in the first Test in Galle, winning by 10 wickets with the hosts only managing 325 runs across the two innings.
However, that all changed in the second Test where Australia failed to capitalise on first-innings centuries from Marnus Labuschagne and Steve Smith.
The Australians had been 2-204 before being bowled out for 364. In reply, Sri Lanka were relentless led by Dniesh Chandimal who made an unbeaten 206 as they reached 554.
That deficit was too much for Australia who collapsed again after being 0-49 to be bowled out for 151 with Prabath Jarasuriya taking 6-59 to finish with 12 wickets for the game.
“It’s a good reality check for people touring over here that it’s really hard,” Cummins said.
“So many positives out of last week that we did find methods that work, and one small hiccup doesn’t mean you have to change everything.”
Australia will face India in a four-game Test series in the subcontinent next year, which looms large in their plans.
“We’ll review this series, try to put away lots of notes and ideas, then bank that, put that to one side and work towards the home summer,” Cummins said.
“In Australia most likely you only play one spinner, so in the background you’re trying to prepare a couple of other guys so they get the chance over in India.
“The last two tours we’ve learned a heap, we’ve come a long way in how we’ve played and try to park that to one side and try to re-remember it in six months.”