Humbling the hosts by 117 runs at the SSC, India clinched the three-match series 2-1 to register their first series win on Lankan soil after 22 years.
Virat Kohli's side went into the three-match series on 97 points and has gained three rankings points after coming from behind to win its first overseas Test series victory since 2011.
It was also Kohli's first Test win as captain after taking over the reigns of the team from Mahendra Singh Dhoni.
Angelo Mathews' men, meanwhile, remain in seventh place but have dropped three rankings points.
South Africa are comfortably perched at the top of the rankings with Australia a distant second.