Eyeing their eighth title of the season, Indian tennis ace Sania Mirza and her Swiss partner Martina Hingis entered the semi-finals of the doubles event at the China Open in Beijing Thursday. The top seeds managed to prevail over the German-Czech pair of Julia Goerges and Karolina Pliskova 7-6, 6-4 in their quarterfinal match.The Indo-Swiss combination has bagged seven women's doubles titles this year so far, including two Grand Slams at the Wimbledon and the US Open, since they started playing together in March.