(CNN) -- Maria Sharapova stayed on course for her first tournament victory since returning to the WTA Tour with a battling three-sets victory over Alisa Kleybanova in the Toray Pan Pacific Open on Wednesday.
Sharapova was delighted to come through a tough third round match in Tokyo.
Sharapova came from a set down to beat her fellow Russian 2-6 6-2 6-2 to reach the quarterfinals of the tournament in Tokyo for the fourth time.
Former world number one Sharapova has clawed her way back to 25th in the world after being sidelined for nine months following shoulder surgery last year.
But a title has eluded the tennis icon with the $2 million event in the Japanese capital representing an excellent opportunity after a string of seeds have exited.
World number one Dinara Safina, Venus Williams and Svetlana Kuznetsova all departed on Monday, with Elena Dementieva, Caroline Wozniacki and Vera Zvonareva suffering the same fate in Tuesday's play.
Sharapova made a slow start, but once she had leveled in the second set was always in command, securing a pair of breaks in the final set to wrap up victory in a shade over two hours.
Earlier, seventh seed Jelena Jankovic reached the quarterfinals as Russia's Elena Vesnina was forced to retire with a left thigh injury when trailing 6-1 3-0.
Former world number one Jankovic is the highest-ranked player left in the tournament and now faces France's Marion Bartoli, who beat Anastasia Pavlyuchenkova of Russia, 4-6 6-2 7-5.
Jankovic has lost to 14th seed Bartoli twice this year, at the Australian Open and at the WTA tournament in Stanford, California.