Electing to bat first, Sri Lanka wobbled against the disciplined Australian bowlers as they could only make 128 for nine in their stipulated 20 overs at the R Premadasa Stadium.
Dhananjaya de Silva was the top scorer for the hosts with a fighting 62 as Dilshan, who quit the one-day format in the middle of the five-match series, scored just one off three balls in his final international game.
In reply, Australia got off to a blistering start, thanks to Glenn Maxwell once again, who racked up a 29-ball 66 to put the tourists in solid position. In the process, he equalled an Australian record for the fastest T20 50 in just 18 balls.
In an interesting turn of events, Australia then suffered a middle-order collapse, falling from a strong 93-0 to precarious 120-6 in the 17th over.
However, the tourists held their nerves as Travis Head, who remained unbeaten on nine, hit the winning runs to help Australia finish the two-month long tour on a high.
Dilshan, who two wickets in his final international game, was given a standing ovation by a raucous home crowd. He was a member of the Sri Lanka side which shared the ICC Champions Trophy 2002 title with India, and won the ICC World Twenty20 2014 in Bangladesh. (Courtesy ANI)