Simmonds, 20, finished as runner-up at the Soweto Open at the weekend, after she lost 7-6 (3), 4-6, 1-6 to Hungary's Timea Babos in the final of the women's tournament.
SA women's number one Chanelle Scheepers moved three places up to 57th in the singles rankings, despite losing 3-6, 3-6 to former world number one Ana Ivanovic at the Madrid Open last week.
Meanhwhile, SA men's number one Kevin Anderson, in 27th position, retained his ATP singles ranking.
Anderson reached the third round of the Madrid men's tournament, where he was knocked out in straight sets by world number six Tomas Berdych.