Sania Mirza in Japan Open quarters

Indian tennis ace Sania Mirza sailed into the Japan Open quarter-finals after notching up a straight-set win over Ukraine's Viktoriya Kutuzova on Wednesday.

Sania defeated Kutuzova 6-4, 6-3 in one hour and 23 minutes to set up a tough quarter-final against second-seeded Frenchwoman Marion Bartoli.

Both Sania and Viktoriya served badly in the opening set, committing five double faults each.

But Sania managed to convert a crucial break point to go 1-0 up.

The Indian was more in control in the second set and she cut back on her service errors, saving three of the four break points she faced.

Viktoriya, however, continued to serve poorly and was broken thrice by the Indian, who was also helped by the three double faults the Ukrainian committed.