Ashwin now has 904 points, the second best by an offspinner after Muttiah Muralitharan (920), and the fifth-best among spinners after Tony Lock (912), Derek Underwood (907) and Shane Warne (905).
Ashwin, who has scored 239 runs in six innings, including three half-centuries, in the ongoing Test series, also consolidated his position as the No.1 allrounder with 483 points, 78 ahead of the second-placed Shakib Al Hasan.
Ashwin's spin partner Ravindra Jadeja is ranked fourth in the allrounder's list, just one point behind Ben Stokes' 341. Jadeja's six wickets in the Mumbai Test meant he rose to a career-best sixth in the bowlers' list.
India Test captain Virat Kohli, meanwhile, reached a career-best second rank among batsmen after his 235 in Mumbai. The knock earned him 53 points and an average of over 50 in Test cricket too. Australia captain Steven Smith occupies the top spot with 897 points, 11 ahead of Kohli.
Kohli, who is also placed second in ODIs, and first in T20 internationals, has the chance to secure the top ranking in all three formats next year.
India opener M Vijay and offspinning allrounder Jayant Yadav also moved up the batting rankings following their centuries in Mumbai. Vijay jumped up five places to 24th while Jayant vaulted to 56th from 87th.