Clarke was unbeaten on 71 as the tourists, trailing by 157 runs on the first innings, reached 303-4 in their second knock by lunch on the fifth day, a lead of 146 runs with six wickets in hand.

Australia need to play out the remaining two sessions to force a draw and clinch the series 1-0 on the back of the 125-run win in the first Test in Galle.

The second Test in Pallekele ended in a rain-affected draw.

Clarke notched up his highest score in the series to keep the tourists afloat after Sri Lanka had struck an important blow in the day's sixth over.

Australia added just 11 runs to their overnight score of 209-3 when century-maker Phil Hughes top-edged a sweep off Rangana Herath to Lahiru Thirimanne at square-leg.

The left-hander made 126, his third Test century.

Herath, the left-arm spinner who claimed all the four Aussie wickets to fall, shared the second new ball, which was taken in the 87th over with the total 268-4.

Clarke responded to the gamble by driving the spinner through the covers and lofting the next ball for six to bring up his half-century.

Michael Hussey kept his captain company at lunch with 21, the pair having put on 83 runs so far for the fifth wicket.

Copyright AFP (Agence France-Presse), 2011