Bolton the constant in opening shuffle

Opening batter Nicole Bolton feels comfortable in her role at the top of the order as Australia look to settle on their batting line-up ahead of next year's ICC World Cup in England.

The Commonwealth Bank Southern Stars became the first nation to qualify for the event when Bolton led the tourists to a 78-run win over Sri Lanka in the second one-day international to move three games clear on top of the ICC Championship and ensure they couldn't drop out of the top four teams to earn automatic qualification at the end of the calendar year.

Quick Single: Super Stars secure World Cup spot

The left-handed West Australian has been the one constant opening up the innings for the Australians in 50-over cricket since the second ODI of last year's successful Ashes campaign, with three different options trialled during the 10-match time-frame.

Elyse Villani was the go-to option for the series in England, while captain Meg Lanning moved up for the home series against India, before Beth Mooney got the nod for the tour of New Zealand and now the return of Villani for the maiden bilateral series against Sri Lanka.

Bolton and Villani compiled a punishing 81-run stand for the first wicket in Tuesday's clash, laying the platform for the total of 8-254 that would ultimately prove too great for the home side.

While Bolton playfully admitted she 'couldn't hit it off the square' during the early stages of her knock of 64 in the second of four ODIs on the island nation, the 27-year-old says she's happy to play the support role when the batter down the other end is striking the ball as crisply as Villani (45) was at Rangiri Dambulla Stadium.

"'Motty' (coach Matthew Mott) is pretty clear on what he expects from me, so my role doesn't really change," Bolton said of the game plans with different opening partners.

"It's always different with another partner, but I've played enough cricket with these girls that whoever is up the top we can get the job done.

"With Elyse yesterday we had a good partnership to get the team off to a good start, so we're looking to do that over the next two games as well."

While the reigning world champions have locked in a spot to defend their title next year, the Southern Stars are determined to first finish the year as the inaugural winners of the ICC Championship.

Australia will go a long way to securing the title with a clean sweep in the final two ODIs against Sri Lanka at R. Premadasa Stadium in Colombo on Friday and Sunday, before returning home for a series against South Africa in November.

Quick Single: Brilliant Blackwell joins the legends

"We're just taking every series in isolation," Bolton said following the team's four-hour bus trip from Dambulla to Colombo.

"We're looking to win every game and sit on top of that table so when we do get to the World Cup we've got a lot of momentum."

The ICC Championship has resulted in a more structured scheduled over the multi-year cycle, while offering the opportunity for a more diverse fixture in terms of both opponents and venues.

It's a system that will likely help bridge the gap between the typically strong nations and those still developing in the increasingly professional game around the world.

"There aren't too many times you get to play against countries like Sri Lanka and South Africa," Bolton said.

"It's always the main countries like England and New Zealand that we've always come up against.

"You never really see Sri Lanka and these countries until the World Cup, so they're always the unknown.

"Now we can actually have some planning to make sure that we're in the right space into series and also World Cups."