Fourth seed Sania Mirza [Images] stayed on course for a medal as she stormed into the singles quarter-finals with a facile victory, but teammate Shikha Uberoi retired from the event due to exhaustion, in the tennis competition at the Asian Games in Doha on Sunday.

Sania thrashed Korean Yoo Mi 6-1, 6-4 in a match that lasted 52 minutes. The Indian star faced no competition, outplaying Yoo Mi with a powerful serve and volley game.

Sania has been playing continuously for the last three days but she did not show any signs of fatigue as she hammered her way past Yoo Mi.

Sania's first serve was good and that helped her wrap up the match quickly as Yoo Mi found it tough to negotiate it. The 20-year-old Hyderabadi broke Yoo Mi in the third, fifth and seventh games to win the first set 6-1 in 18 minutes.

However, Yoo Mi put up good resistance in the second set, which went on for 34 minutes. Sania broke the Korean in the second but failed to hold on to her serve in the third game. The Indian, however, hit back strongly to break the Korean in the fourth and eighth games and wrap the set 6-4 and the match.

Shikha Uberoi opted to retire against second seed Zheng Jie of China. She conceded the match giving exhaustion and exertion as the reason. She had a long day on the court on Friday and then played a singles, doubles and a mixed doubles on Saturday.

The Indian chose to preserve her energy for the doubles today rather than waste it against a tough opponent.