India's P V Sindhu and Sameer Verma advanced to the quarter-finals with straight game wins but Parupalli Kashyap bowed out of the Korea Super Series badminton following a narrow defeat in the second round, in Seoul today.Olympic silver medallist Sindhu saw off Thailand's Nitchaon Jindapol 22-20, 21-17 to set up a clash with Japan's Minatsu Mitani, who was a bronze medallist at the 2014 World Championships and had also defeated Saina Nehwal in the finals to clinch the 2012 French Open.Hong Kong Super Series finalist and Syed Modi Grand Prix Gold winner, Sameer defeated Hong Kong's Wong Wing Ki Vincent 21-19, 21-13 in 41 minutes and he will need to raise his game by a few notches when he faces local hot favourite Son Wan Ho.Son Wan had to dig deep to end Kashyap's run in men's singles. He battled for an hour and 16 minutes before getting the better off the Indian 21-16, 17-2, 21-16 to reach the last-eight stage.