Things hadn't been going to plan in Sri Lanka for Test hopeful Shaun Marsh.

Omitted from the one-day side for the first three matches of the five-game series after two single-figure scores in the tour-opening Twenty20 matches, Marsh had to content himself with hours of work in the nets with batting coach Justin Langer.

But that hard work paid dividends in Colombo on Saturday as Marsh scored a composed 70 to guide Australia to their victory target of 133 and a series-clinching win in the fourth ODI.

And the West Australian said he was confident once he got his chance he'd be able to shine.

"Obviously it was disappointing with the Twenty20s but that's the way they went in the first game (ODI selectors) and obviously I was disappointed but it gave me a chance to work really hard against the spinners," Marsh told reporters on Sunday.

"I've really enjoyed working with Justin Langer ... going into the game last night I felt really confident with the work I've done over the past couple of weeks to go out there and perform."

Perform he did, joining Sri Lanka's Mahela Jayawardene as the only batsman to pass 50 in a match dominated by the ball.

His innings prompted captain Michael Clarke to suggest Marsh had single-handedly delivered the win for the Australians, a big rap as Marsh tries to earn himself a Test debut in the upcoming three-match series.

But Marsh insists he's not worried about the longer format of the game just yet with one more one-day clash remaining.

"Look it's important for the one-day game," Marsh said about the chance to gain some form.

"To be honest with you I haven't really thought about the Test matches, we've still got one game left in this series and I have to prove myself in the one-day side let alone the Test team."

Australia's one-day series against Sri Lanka concludes with game five from Colombo's Premadasa Stadium on Monday from 2.30pm local time (1900 AEST).

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