Talk about lone rangers, Sanath Jayasuriya single handly won that October 2000 Coca Cola cup triseries in Sharjah for Sri Lanka, scoring career best 189 runs as rest of other Lankan batters struggled throughout the innings.
Set exactly 300 runs to chase, Indians slipped to their lowest total ever, 54, as Chaminda Vaas swung the ball both ways under lights. It was the final match, and Sri Lanka won by mamoth 245 runs which is still the biggest win margin in India vs Sri Lanka one day internationals.
India's largest ODI win over Sri Lanka was recorded in ICC World cup 2003. electing to field first, Lankans first failed to restrict Indians and then were allout in just 23 overs for 109 runs chasing 293. Javagal Srinath and Ashish Nehra were main nemesis that day, picking 4 wickets each and registering a big 183 run win.
By wickets : India have one 10 wkt win over Sri Lanka (Sharjah, Apr 1984) which they acheived chasing smallish 97. For Sri Lanka, they once won by 9 wkts at Premadasa stadium in Colombo, chasing 227.
Recently, stasticians have started to highlight wins with balls remaining as well. So, the most number of balls remaining before a team won in India vs Sri Lanka ODI is 178, achieved by India when they had to chase 123 at home ground Mohali on 28 October 2005. 103 balls remaining is Sri Lanka's best win result, which they found at Margoa, chasing down 137 for the loss of only 3 wkts back on 8 December 1990.
Smallest victory margin in India vs Sri Lanka one day match belongs to India, for their 1 run win at Khettarama stadium in Colombo back on 25 July 1993. Invited in to bat first, Indians suffered a middle order collapse after solid 77 run partnership for opening wicket between Manoj Prabhakar and Navjot Sidhu. Chasing moderately small 213, Lankans were 161/2 before falling to 211 allout against likes of Rajesh Chauhan, Anil Kumble, Javagal Srinath who all took 2 wickets each.
Sri Lanka's 2 win victory came against India at RPS, Colombo. Chasing a huge 303, Indians were no were in hunt = 4 for 64 when captain Sachin Tendulkar departed. Then, a miracle stuck = Mohammad Azharuddin (111*) + Ajay Jadeja (119) = 223 runs 5th wicket partnership. Sadly, they couldn't complete that unlikely win, falling short by a couple.