Left-arm seamer Chanaka Welegedara took two wickets in succession - having Mitchell Johnson caught by Rangana Herath and Peter Siddle caught by Tharanga Paranavitana at slip. Welegedara returned 3-75.
Eranga then bowled Hussey after the left-hander had faced 178 balls, smashing two sixes and 12 boundaries. Hussey scored 118 runs - his 15th test hundred following up his top score of 142 in the second test and 95 in the first.
Shaun Marsh, who batted at No 3 ahead of regular Ricky Ponting, scored 81 after scoring 141 on his debut in the second test.
Hussey's century took him past the magic mark of 5000 test runs, scored at an average of nearly 53.
The 36-year-old Hussey enjoyed a considerably higher average than that in his remarkable introduction to cricket, although time and the ability of attacks to work him out a bit would inevitably impinge on that startling average.
However, he is still scoring either a century or a 50 in two out of every five innings.
He made the 5000 run mark faster than any other Australian (including Ponting) except for iconic names such as Don Bradman, Greg Chappell, Neil Harvey and Matthew Hayden.
Australia lead the three-test series 1-0 after winning the first test and drawing the second.
