The 26-year-old Hyderabadi rose from No 11 despite not playing any tournament this week as a result of other players dropping points.
Sania won back-to-back titles the China Open and Pan Pacific Open in Tokyo, earlier this month.
Her partner, Cara Black of Zimbabwe, too gained a place, rising to No 13.
Italians Sara Errani and Roberta Vinci held on to the joint-No 1 ranking, while Su-Wei Hseih climbed two spots to No 4 and Katrina Srebotnik moved one up to three.
Image: Sania Mirza
I am a better player than last year: Sania Mirza
Now, Sania Mirza wants to be No 1 and win a women's Grand Slam
Mirza-Black shock Errani-Vinci to reach China Open final
BEST Sports Photos of the Week!
Kerber seals final spot at WTA Tour year-ender