Saina, who advanced to the women's singles quarterfinal at the ongoing World Championships in Guangzhou, was overtaken by Thailand's Ratchanok Intanon.
Saina's compatriot P V Sindhu managed to retain her 12th position in the world rankings.
In the men's singles rankings, Parupalli Kashyap slipped four places to the 17th spot while R M V Gurusaidutt jumped a spot to a career-best 20th position. Ajay Jayaram, who crashed out in the second round of the World Championships, was static at 24th position.
However, no Indian features in the top-25 of the doubles rankings in any category.