INDIAN WELLS, California Australian Open champion Maria Sharapova, holder Daniela Hantuchova and second seed Svetlana Kuznetsova reached the Pacific Life Open quarter-finals in contrasting styles on Tuesday.
Fourth seed Sharapova, winner at Indian Wells Tennis Garden in 2006, maintained her perfect start to the season but had to work hard to beat Ukrainian Alona Bondarenko 6-2 5-7 6-4.
Twice champion Hantuchova beat India's Sania Mirza 6-1 7-6 in the first match of the day before Kuznetsova swept past 17-year-old Caroline Wozniacki of Denmark 6-2 6-3.
Sharapova, who won her third grand slam crown at the Australian Open in January before claiming her 18th WTA title in Doha, was relieved to win her 17th successive match this year.
The 20-year-old Russian came back from an error-prone second set to break Bondarenko in the ninth game of the third before sealing victory in just under three hours.
"I felt like I was pretty close to being down and out because I wasn't able to produce good points for a long period of time," world number five Sharapova told reporters.
"I would play a good game, I would get down again and then I would miss three returns in a row. I was just giving her so many opportunities out there.
"I wasn't playing my best tennis, far from it, but I was just tough in the end and it gets me through a lot of matches."
Hantuchova held off a strong fightback by Mirza to wrap up victory in one hour, 55 minutes and set up a quarter-final with Sharapova.
"I thought it was a great match," the fifth-seeded Slovakian said. "Sania is a great hitter and I was expecting a really tough one today. Just being able to be in the quarters without losing a set feels really great.
"I feel like I'm hitting the ball well again," added the 24-year-old, who claimed her first WTA career title at Indian Wells in 2002. "I'm doing it the same way as last year so those two are pretty good signs. We'll see what's going to happen."
Hantuchova, who beat Kuznetsova in last year's final, broke Mirza in the second and fourth games to storm through the opening set in 39 minutes.
After trading an early service break in the second set, the elegant Slovakian broke again in the 11th game, when her opponent double-faulted, to lead 6-5.
Although Hantuchova then lost her own serve, she clinched the tiebreak 7-4, sealing victory with a crunching backhand down the line.
In other matches, top-seeded Serb Ana Ivanovic came from a set down to beat Italy's Francesca Schiavone 2-6 7-5 6-2 and will next meet Russian Vera Zvonareva, a 6-7 6-0 6-4 winner over Australia's Casey Dellacqua.
Third-seeded Serb Jelena Jankovic brushed aside Spaniard Anabel Medina Garrigues 6-3 6-3 to set up a quarter-final clash with twice former champion American Lindsay Davenport, who upset sixth seed Marion Bartoli of France 6-2 7-5.
(Editing by Ed Osmond)