Mitchell Starc tears visitors apart as Tim Paine and co. win by 366 runs at Canberra, sweep Test series.
Starc picked up a five-for while Khawaja cracked a fine hundred to ensure Australia found themselves in command at stumps on Day 3.
Sri Lanka lose three after Karunaratne retires hurt. Earlier Aussies declared 5-534.
They made centuries in a 308-run stand, taking advantage of four drops in the field from the visitors.
The home side will take in an unchanged XI as they look to end the season with a 2-0 series win over Sri Lanka.
The fast bowler took 10 wickets for the match as Sri Lanka slid to an innings loss inside three days.
The duo stitched a stand of 166 to help the hosts gain a lead of 179, while Lakmal snared five scalps for Sri Lanka
Australia bundled out Sri Lanka for 144 before they reached 72 for two to put the hosts on top.
Jhye Richardson replaces injured Josh Hazlewood for two-match Test series against Sri Lanka
Will Pucovski earns surprising Australia call-up for Sri Lanka Tests; Marsh brothers, Aaron Finch dropped.
