Sania earned 470 points, which pushed the Indian to fifth, replacing her doubles partner Su-Wei Hsieh. Sania had achieved the top-5 rank last year too in July.
Sania had a great 2014 season and she has made a decent start to the new season, reaching the semifinals at Brisbane event and winning the title in Sydney.
"Being in top-five of the world in any field feels amazing and it's wonderful to have achieved my career-best rank this week. But if I stay away from injuries, I feel I could go further in the coming months," Sania said.
From Monday onwards, Sania will be seen in action at the Australian Open where she and Su-Wei are seeded second. They open their campaign against Argentina's Maria Irigoyen and Swiss girl Romina Oprandi.
Sania may meet her last season's partner Cara Black in the second round, provided both of them clear the first round.
Zimbabwe's Black and her Chinese partner Saisai Zheng are up against Gabriela Dabrowski of Canada and Alicja Rosolska of Poland.
Image: Bethanie Mattek-Sands and Sania Mirza
Photograph: Brendon Thorne/Getty Images