Fatullah: Sangakkara slammed his 18th ODIhundred as Sri Lanka chased down the 265-run target in 49.2 overs.
Jadeja jolted Sri Lankan chase when he dismissed Mahela Jayawardene and Dinesh Chandimal on consecutive deliveries to leave them struggling at 148/4 in 31.2 overs.
Pacer Mohammed Shami also joined the party dismissing skipper Angelo Mathews to put India on top.
Sri Lanka suffered another blow in quick succession when Shami claimed his second wicket in the form of Sachithra Senanayake.
Ravichandran Ashwin broke the crucial second wicket stand between Kusal Perera and Kumar Sangakkara by removing the former.
Perera played a fine knock of 64 studded with four fours and two sixes. Ashwin struck at the time when India were desperately looking for breakthrough.
With Perera's dismissal, Ashwin also completed his 100 wickets in the ODIs.
India finally got a breakthrough when spinner Ashwin struck to dismiss Sri Lanka's Lahiru Thirimanne.
Kusal Perera led the Sri Lankan charge from the front slamming his third ODI fifty and continued to defy Indian bowling attack. Perera smashed three fours and two sixes during the course of his fifty.
Openers Thirimanne and Perera started off well to lay the foundation for Sri Lankan chase against India.
The duo had no problem negotiating Indian bowlers as they completed 50-run stand in the 10th over and went on to add 80 runs for the first wicket.
The luck was not going India's way when Ravindra Jadeja almost caught Kusal Perera at mid wicket but could not hold on to it when his elbows hit the ground.
Earlier, opener Shikhar Dhawan missed out on a century by six runs as spinner Ajantha Mendis returned to haunt India by restricting them to 264 for nine.
Sent into bat, Dhawan (94) and captain Virat Kohli (48) led India's recovery in a 97-run second-wicket partnership, before Mendis, more than three years after his mystery was decoded by the Indian batsmen, came back to trouble them with figures of 4/60 at the Khan Shaheb Osman Ali Stadium.
Mendis castled Kohli and Dhawan with his carrom ball while off-spinner Sachitra Senanayake scalped 3/41 as India's new-look middle order sorely missed Mahendra Singh Dhoni.
Thanks to the duo's exploits, India slipped after being comfortably placed at 175 for two in the 36th over.
Ajinkya Rahane (22), Ambati Rayudu (18) and Dinesh Karthik (4) looked good but could not covert their starts, while Stuart Binny did not trouble the scorers after being out for a zero.
Rohit Sharma, particularly, struggled against the odd ball as Sri Lanka, who were playing with three specialist spinners, brought on offie Senanayake in the sixth over.
Lanka seemed in perfect control, conceding only 37 runs in the first power play which also yielded Sharma's wicket.
After all his struggle, Sharma'a anxious stay finally came to an end when he got to out to a dubious decision. Umpire Nigel Llong ruled the batsman out despite being long way down the track.
The breakthrough incidentally turned around India's fortunes with last match centurion Kohli starting off with a boundary.
At the other end, Dhawan looked to have got his fluency back and Kohli's reassuring presence further calmed the left-hander's nerves.
Sri Lanka's pace attack lacked bite after skipper Angelo Mathews left the field midway into his third over with a niggle as the Lankans resorted to an all-spin attack with Mendis coming into bowl in the 16th over.
With Kohli in exquisite form and Dhawan back among runs, the duo looked in control of the proceedings.
Dhawan completed his half-century in 68 balls, the left-hander's first 50-plus score in nine matches. Kohli punished Chaturanaga de Silva before Dhawan joined the party with a boundary and a six against Perera, as India raced to 128/1 in 26 overs, when a smart decision to bring in Mendis from the pavilion end did the trick.
Earlier, Sri Lanka have won the toss and put India to bat.
Sri Lanka have three spinners today - Ajantha Mendis comes in for Lakmal.
India have brought in Stuart Binny for Varun Aaron.
Teams:
India: Shikhar Dhawan, Rohit Sharma, Virat Kohli (Capt.), Ajinkya Rahane, Ambati Rayudu, Dinesh Karthik (wk), Ravindra Jadeja, Ravichandran Ashwin, Bhuvneshwar Kumar, Mohammed Shami, Stuart Binny.
Sri Lanka: Kusal Perera, Lahiru Thirimanne, Kumar Sangakkara (wk), Mahela Jayawardene, Angelo Mathews (Capt.), Thisara Perera, Chaturanga de Silva, Dinesh Chandimal, Sachithra Senanayake, Lasith Malinga, Ajantha Mendis.
Brief scores
India 264 for 9 (Dhawan 94, Mendis 4-60, Senanayake 3-41)
Sri Lanka 265 for 8 (Sangakkara 103, Kusal Perera 64, Jadeja 3-30, Shami 3-81)
Result Sri Lanka won by 2 wickets
Points Sri Lanka 4, India 0
MOM Kumar Sangakkara (Sri Lanka)