Australia broke a nine-year record held by Sri Lanka, who scored 260/6 against Kenya in 2007.
Australia piled up the highest ever total in a Twenty20 international on the way to a crushing 85-run victory over Sri Lanka in Kandy on Tuesday.
Glenn Maxwell smashed 145 not out off 65 balls, including nine sixes and 14 fours, to propel the touring side to a score of 263 for three, beating Sri Lanka's 260 for six against Kenya in 2007.
The hosts never looked like getting close to their massive target, Dinesh Chandimal top-scoring with 58 as they stumbled to 178 for nine.
Pacers Mitchell Starc and Scott Boland claimed three wickets each for Australia.
The hero of the match Maxwell, who registered his maiden T20 century in his 35th game, found the perfect partner in Usman Khawaja, who scored 36 off 22 balls, as the duo put together 97 runs for the second wicket.
Debutant left-arm spinner Sachith Pathirana got Khawaja trudging back to the pavilion, only to see Travis Head join forces with Maxwell.
Maxwell and Head, who scored an 18-ball 45, then put on 109 runs for the third wicket as there were raining boundaries at a packed Pallekele International Stadium.
Maxwell fell 11 runs short of teammate Aaron Finch's top T20 score of 156 as he faced a single ball in the final over of the innings.