Lyon - must think Test cricket is an easy game.

Nathan Lyon claimed a five-wicket haul on debut as 16 wickets tumbled on day two of the opening Test between Sri Lanka and Australia in Galle.

The end result was Australia finishing on 115 for six, which gives them a commanding lead of 283 after they dismissed the hosts for a lowly 105 - their lowest total at home in five years.

It took Michael Clarke's bowlers under two sessions to bowl Sri Lanka out and debutants Trent Copeland and Lyon led the way. Fast bowler Copeland, who was given the new ball along with Ryan Harris, removed Sri Lanka captain Tillakaratne Dilshan with his second ball after his first was smashed for four. Ricky Ponting produced a brilliant, diving catch at short cover.

Lyon went one better than Copeland and became only the second Australian to pick up a wicket with his first ball in Test cricket after slip fielder Clarke threw himself to the left to take a diving catch to get rid of Kumar Sangakkara for 10. Mahela Jayawardene (11) looked in good nick, but a mix-up with Tharanga Paranavitana cost him his wicket.

Shane Watson tore the heart out of the Sri Lankan middle order after lunch as he removed Thilan Samaraweera (26), Prasanna Jayawardene (duck) and Paranavitana (29) in his first three overs of the match. All three went lbw after being hit right in front. Prasanna and Paranavitana both referred their dismissals to the third umpire, but the replays only confirmed the on-field official's decision and Watson finished the innings with three wickets for six runs in 11 overs.

The dismissal of Paranavitana was the crucial wicket for both teams as the left-handed opener was the mainstay for the Sri Lankans and his departure allowed Australia to attack from both ends.

Spinner Lyon did exactly that as he wrapped up the tail to finish with five for 34. Angelo Mathews was bowled for five, Suraj Randiv departed for nine and Rangana Herath's slog-sweep ended up at midwicket. Lyon completed his five-for with a stunning return catch off Chanaka Welegedara's bat.

With the pitch offering plenty of assistance to both fast bowlers and spinners, Australia's 168-run first-innings lead was always going to be handy, but it may yet turn out to be crucial after Sri Lanka picked up six wickets in the final session.

Watson went first ball after nicking Welegedara to gully and Ponting lost his bat and his wicket as his attempted pull was skied. Phillip Hughes and Clarke remained positive despite the two early wickets and took the attack to the bowlers. They eased the nerves with a 56-run stand, but Hughes fell lbw for 28 after getting his sweep wrong.

Clarke went to his 21st Test half-century but he got a reprieve on the way when the umpire gave him out lbw to Dilshan. The right-hander reviewed the decision and the replays showed the ball was missing leg stump. He finally departed for 60 when he skied Herath. Hussey (15) fell the next ball after the television umpire found the ball to have brushed his glove before it popped to short-leg. Umpire Richard Kettleborough again got it wrong but he was forced to change his decision after another review.

Brad Haddin never looked comfortable and lasted only five balls before nicking Herath to slip. Usman Khawaja and Mitchell Johnson toiled for a few overs before play for the day was called off due to bad light and rain.