Replying to Sri Lanka's 642, India were 95 for no loss, trailing by 547 runs at close on day two of the second cricket Test in Colombo on Tuesday.
Day two saw only two wickets fall and as many as 425 runs being scored on a placid Sinhalese Sports Club.
It was yet another day of toil and frustration for the Indian bowlers who failed to make much of an impression against the Lankan batsmen, who scored at a brisk pace right through the day.
Sehwag (64) and Murali Vijay (22) batted in contrasting fashion as India survived 18 overs in the last session of the day without a blot on its scorecard.
The sound start, best in the series so far, also lifted the gloom over the India camp as they worked hard without much success in the field for more than five sessions.
Perched on top the Test rankings, India need to win this match as a defeat would not only take away their number one rank but also extend their winless streak in a Test series in the Island nation.
Earlier, Sri Lanka declared their first innings after scoring 642 for four.
Virender Sehwag removed Kumar Sangakkara just after the lunch, but not before the Sri Lankan captain registered his seventh double century.
Sangakkara made 219 before Rahul Dravid took a sharp catch at slip off Sehwag to give India a rare moment of joy.
Sangakkara scored his runs in 335 balls and was laced with 29 hits to the boundary.
After Sangakkara's departure, new man in Samaraweera quickly got into the groove as he turned away a Pragyan Ojha delivery between slip and backward point for his first boundary.
He then hit a Harbhajan Singh's short and wide delivery to the fence.
On the other hand, Jayawardene looked composed and negotiated the Indian bowlers with ease.
Bruised and battered by the Lankan batters, the Indians committed numerous errors in the field as Jayawardene and Samarweera stepped up the accelerator to enable their captain declare after a safe first innings total.
Jayawardene and Samarweera's 100-run stand came off just 137 balls as the two capitalised on the listless Indian attack.
Jayawardene treated Indian bowlers with disdain as he dispatched Abhimanyu Mithun over the long-on boundary.
Earlier, Sangakkara's seventh double century came in 301 balls with 27 hits to the boundary.
Brief score:
Sri Lanka 1st innings: 642 for four in 159.4 overs (Kumar Sangakkara 219, Mahela Jayawardene 174, Tharanga Paranavitana 100; Virender Sehwag 1/71).
India 1st innings: 95 without loss in 18 overs (Virender Sehwag batting 64, Murali Vijay batting 22).
