Laxman defied cramps and anchored the innings brilliantly to notch up his 16th Test hundred, while Sachin Tendulkar (54) and Suresh Raina (41 not out) were the other notable contributors as the visitors overhauled a target of 257 about 10 minutes before the tea break.
Raina clobbered Chanaka Welegedara for a six to hand Sri Lanka their first defeat at P Sara Oval Stadium since August 1994, triggering scenes of celebration in the Indian dressing room.
Chasing 257 on a rather difficult fifth day track, the Indians recovered from early blows suffered yesterday with a 109-run partnership between Laxman and Tendulkar that laid the foundation of the win.
Resuming the chase from yesterday's 53 for three, India lost night-watchman Ishant Sharma (4) early in the morning.
Ishant was caught at short mid-wicket by Kumar Sangakkara off Suraj Randiv in the morning. Randiv ripped in a flighted loopy delivery around off and middle stump, leaving Ishant bemused who looked shaky right from the start.
Image: Sachin Tendulkar bats during the fifth day of the third and final Test between India and Sri Lanka in Colombo, Saturday, Aug. 7, 2010.