Hobart, Feb 26 : India were at 47/1 after the end of ninth over in response to Sri Lanka's total of 179 runs at the Bellerive Oval.
Lankan pace spearhead Lasith Malinga drew first blood for his team as he claimed the wicket of opener Robin Uthappa early on in the Indian innings.
Uthappa lobbed an easy catch to Amerasinghe at a score of 11 runs as India were 18 runs for the loss of a wicket.
Earlier, Sri Lanka made a mess of a flat batting track in Hobart, limping to 179 in a game they have to win to stay alive in the CB Series.
In what was a sloppy display, Sri Lanka skid from a comfortable 1 for 72 to a perilous 7 for 93 before Chamara Kapugedera's fifty lent some respectability.
India's seamers swung the ball around in overcast conditions. Praveen Kumar triggered the collapse with three wickets in as many overs before Ishant Sharma pierced the soft underbelly with a deep incision.
Kumar Sangakkara's poor shot selection opened up the floodgates and the rest seemed more intent to catch the next flight out of Hobart. On a flat pitch, they saw their chances of entering the final all but go up in smoke.
Sri Lanka were cruising along when Sanath Jayasuriya and Sangakkara were out in the middle. The duo had shrugged off the early dismissal of Dilruwan Perera, castled by a peach of a straightener from Ishant, by cashing in on a slightly wayward new-ball spell.
Everything changed when Praveen Kumar was introduced in the attack. Playing only his third ODI, he showed why he's so highly rated in the domestic circuit.
Sangakkara paid the price for taking Kumar too lightly: he walked down the track and poked recklessly, only to see Mahendra Singh Dhoni pull off a fine catch diving to his left.
Kumar was ecstatic after his first international wicket but he was to nab two more in quick time. Mahela Jayawardene was undone by a sharp catch by Rohit Sharma at point before Chamara Silva wafted at one that shaped away to watch Dhoni pull off another fine take.
Jayasuriya, watching all the mayhem from the other end, thought it was best to break the shackles. Faced with a short ball from Irfan Pathan he attempted a high-risk pull, kicking the ground as the ball ballooned into Dhoni's gloves.
Ishant returned to removed Tillakaratne Dilshan, with a peach that swung into his pads, before tempting Chaminda Vaas with an indiscreet pull.
Kapugedera found an able ally in Lasith Malinga and the duo went about playing time rather than over ambitious shots. The pair went without a boundary for 12.2 overs before Kapugedera began to gradually open out.
The innings might have ended early if Sachin Tendulkar hadn't dropped Malinga on 8. But Muttiah Muralitharan also showed some gumption towards the end as Kapugedera completed a well-deserved 57, his highest score.
Praveen Kumar returned to clean up Murali before Harbhajan snapped up his only wicket to keep Sri Lanka down to 179.