Saina Nehwal today started her campaign by beating lower-ranked Olga Golovanova of Russia in straight-game of the World Badminton Championships in Guangzhou, China today.London Olympics bronze medalist Saina beat Olga, 21-5, 21-4, in just 23 minutes to set up a clash with 15th seed Thai Porntip Buranaprasertsuk in the pre-quarterfinals tomorrow.Earlier, World number 12, P V Sindhu overcame a fighting Kaori Imabeppu of Japan to secure her place in the third round of the women`s singles competition. Both Saina and Sindhu had got a bye in the first round.However, World no. 24, Ajay Jayaram lost to Pablo Abian in a 31-minute contest in the men`s singles. In men`s doubles, pair of Tarun Kona and Arun Vishnu crashed out of the tournament after suffering a 15-21, 21-13, 17-21 defeat against 15th seeded Indonesian pair of Alvent Yulianto Chandra and Markis Kido.