Off-spinner Lyon, a controversial selection for the tour, took a wicket with his very first ball and ended with 5-34 as Sir Lanka crumbled to 105 all out.
Australia, who scored 273 in their first innings, reached 115-6 after a collapse of their own, but still led by 283 runs on a deteriorating wicket.
16 wickets fell Thursday with Australian all-rounder Shane Watson chipping in with three wickets in 10 balls, while another newcomer Trent Copeland struck in his first over.
But it was Lyon who made the biggest impression, becoming only the 14th bowler in Test history to take a wicket with his first ball as he removed Kumar Sangakkara, caught at slip by Michael Clarke.
Watson played havoc with the Sri Lanka middle order as he removed Thilan Samaraweera, Prasanna Jayawardene and Paranavitana, all trapped leg before wicket to reverse swing.




