Maria Sharapova defeated Lucie Safarova of Czech Republic to reach the quarterfinals of the Japan Open on Wednesday.

Second-seeded Sharapova continued to experience the difficulties with service game that gave Briton Heather Watson a shot at winning their second-round match, taking only five of them for a 6-2, 7-6(5) win.

Luckily for her, the Czech player showed little resistance in the first set, allowing the Russian to break all of her serves.

Sharapova broke twice in the second set with Safarova serving for the set, needing the tie-break to take it.

In the quarters, the 25 year old will face eighth seed Sam Stosur, who eliminated Slovakia’s Dominika Cibulkova 6-4, 7-5.

This will be their 12th clash, with the 28-year-old Australian having one victory so far, gained at the last year’s WTA Championships in Doha.

Another quarterfinal pair will see Sharapova’s compatriot Nadia Petrova playing against Italy’s Sara Errani.

Petrova, seeded 17, stuttered past Croatia’s Petra Martic, racking up 15 aces to snatch a 7-6(2), (1)6-7, 6-4 win.

Sixth-seeded Errani had nearly as difficult a test in her third-round match against France’s Marion Bartoli, pulling out the match from one set down 3-6, 6-2, 6-2.

Elsewhere, Germany’s fifth seed Angelique Kerber breezed past Urszula Radwanska of Poland 6-1, 6-1 to book an encounter with either world No. 1 Victoria Azarenka or 14th seed Roberta Vinci.