Sri Lanka A 8 for 247 (Silva 104*, Doherty 3-55) beat Australia A 5 for 246 (Voges 81, Birt 52, Udana 3-67) by two wickets
Chamara Silva sent a strong reminder of his abilities to the national selectors with a counterattacking 84-ball 104 that swept the visitors to a thrilling two-wicket victory and sealed the series 2-0.
Chasing 247 in a 40-over match at the Allan Border Field, Sri Lanka seemed to be out of the game when they stuttered to 88 for 5 after 19 overs before Silva revived their hopes through a 72-run stand with Kosala Kulasekara. Australia were still in charge when Kulasekara holed out to Travis Birt in the 33rd over with the visitors needing 87 off 45 deliveries.
A flurry of sixes from Silva, who made only his second hundred in 185 List A matches, and brisk cameos from allrounder Thissara Perera and Sachithra Senanayake took Sri Lanka to the target with five deliveries to spare.
Both sides had agreed 40 overs-a side due to concerns about the fading afternoon light in Brisbane. Australia struggled early on after being sent in on a pitch that offered some assistance to the bowlers. Adam Voges' 89-ball 81 was the cornerstone of their innings, with Matthew Wade and George Bailey also offering support.
It was left to Travis Birt's big hitting to push Australia's run-rate past six. He bludgeoned four sixes and four fours in a 22-ball 52 to set a tough target, but Silva's brilliance ensured it the Sri Lankans took the one-day series after losing both the first-class matches and the Twenty20s.
"It's obviously pretty disappointing as we really wanted to finish the series with a win," the home side's captain, George Bailey, said. "I thought we batted well on a pitch that offered a bit to the bowlers but as it turns out, it wasn't quite enough.
"All credit goes to Sri Lanka and the way they fought back with the bat; we were in a strong position when we had them five for less than 90, but they slowly worked their way back into the game and Silva was very impressive."