By Keiran Williams
BRISBANE, Australia (Reuters) - Australia's batting frailties were quickly exposed by Sri Lanka before Marnus Labuschagne and Travis Head steadied the innings to help the hosts reach 159 for four at tea on day two of the series opening day-night test at the Gabba on Friday.
Labuschagne was 36 not out and Head was 29 at tea, with Australia holding a lead of 15 runs after they had lost both overnight batsmen within the first three overs of the day.
Resuming at 72-2, Marcus Harris (44) could only add four runs to his overnight score before chipping a simple catch to Lahiru Thirimanne at point off Lahiru Kumara in the first over of the day.
Nightwatchman Nathan Lyon (one) fell three overs later when he edged Suranga Lakmal to Kusal Mendis at second slip who took the catch diving forwards to reduce Australia to 82-4.
Head and Labuschagne survived big appeals for lbw early in their innings before settling into their unbroken 77-run partnership to give Australia the lead.
Australia had bundled out Sri Lanka for 144 in just over two sessions on Thursday.
Pat Cummins was the pick of the Australian bowlers claiming 4-39 while Jhye Richardson (3-26) made an impressive debut as Australia rolled Sri Lanka in 56.4 overs after Dinesh Chandimal won the toss and elected to bat.
Australia's reply began in tricky conditions under lights on Thursday with Joe Burns making 15 before edging to slip off Lakmal and Usman Khawaja (11) fell just minutes before the close when he played on to his stumps from spinner Dilruwan Perera.
(Editing by Greg Stutchbury)