Guangzhou, Aug 8 (IANS) India's World No.3 Saina Nehwal entered the women's singles quarterfinals of the World Badminton Championships at the Tiange Indoor Stadium here Thursday. The third seed won 18-21, 21-16, 21-14 in 52 minutes against Thai 15th seed Porntip Buranaprasertsuk in a third round match