The Indians put in a disciplined bowling show to restrict Sri Lanka to 181 for eight and then overhauled the target with as many as 15 overs to spare to set up a summit showdown with hosts England on Sunday.
The 2011 World Cup champions maintained their unbeaten track record in this edition of the tournament winning all the four matches and are now gunning for their second Champions Trophy title having shared it with Sri Lanka in 2002.
While Ishant Sharma (3/33) and Ravichandran Ashwin (3/48) were the bowling heroes for India on a cloudy and chilly day at the Sofia Gardens, in-form Shikhar Dhawan (68) and Virat Kohli (58 not out) were the notable contributors with the bat in what turned out to be a completely lop-sided encounter.
Dhawan scored his second ODI half-century and his 77-run opening stand with Rohit Sharma (33) set up the easy victory.
In a tournament where India have flexed their batting muscle, it were the bowlers who came to the party today after India decided to chase.
Even as the afternoon remained overcast, the Sophia Gardens wicket eased out considerably and Lanka's spearheads Lasith Malinga and Nuwan Kulasekara were barely threatening.
There were a few times when the ball missed the edge of the bat, but Dhawan and Rohit were never in great discomfort.
Sharma gave the Indian innings a breezy start, punching Kulasekara through covers and Dhawan matched him with a similar stroke off Malinga, who struggled to find his bowling form on a big day. Malinga actually suffered a bit of humiliation when Dhawan upper cut him for a six at backward point.
As has been a feature in this tournament, Dhawan held one end up and except for lives on 18 and 62 Kulasekara was the luckless bowler -- the left-hander was a picture of confidence. His 50 came off 73 balls and was laced with six fours and a six.