Centuries from Thilakarathna Dilshan and Kumar Sangakkara took Sri Lanka to a mammoth 320 for 4 in Hobart, a score that India will have to overhaul inside 40 overs to keep their qualification hopes alive.
Mahela Jayawardene led a sound start with a restrained Tillakaratne Dilshan at the other end, but Dilshan gradually began to step up after losing his opening partner for 22, in the company of a fluent Kumar Sangakkara, with whom he made Sri Lanka's highest second wicket partnership of 200 runs.
India put Sri Lanka in, hoping to restrict them and have a clear plan for executing the chase but the presence of two set batsmen at the crease against a side that bats deep should worry them.
Kumar Sangakkara was out for 105 in just 87 deliveries which included 2 sixes and 8 boundaries
Dilshan went on to make his highest ODI total and achieved the great feat of having batted the entire 50 overs and was unbeaten on 160, an innings which included 3 massive sixes and 11 boundaries.
Dilshan is now the highest run scorer in the Commonwealth Bank Tri Series.