Dinesh Chandimal has scored an unbeaten 63 as Sri Lanka struggled to 136-5 at lunch on Day 3 in reply to Australia's imposing first innings of 654 in the first cricket test.

Steve Smith has been labelled a tactical “genius” by Australian spinner Matt Kuhnemann after the stand-in skipper helped set up the wicket of Sri Lankan captain Dhananjaya de Silva on Friday.

Rain slows Australia's progress on day three of the first Test against Sri Lanka in Galle as only two wickets fall.

Australia’s batters have feasted on Sri Lanka’s bowling, racking up milestones and dominance on a rain-curtailed opening day of the first test in Galle.

Australia's Usman Khawaja struck a maiden double hundred and Josh Inglis got a century on his test debut against Sri Lanka to power the tourists to a mammoth 654 for six before they declared their first innings on day two of the opening test on Thursday.