Rome:New world number one Maria Sharapova was made to battle all the way before reaching the Rome International quarter-finals with a 6-4, 7-6 (7/3) victory over Denmark's Caroline Wozniacki on Thursday.
Despite being kept on court by a stubborn Dominika Cibulkova for almost three hours until late on Wednesday, the Russian still came out with all her fighting spirit under the sun in the Italy capital on Thursday.
She edged a combative first set and then needed to dig deep to come back from 5-1 and two breaks of serve down in the second to win five straight games.
However, when needing to serve for the match and despite leading 30-15, mistakes crept into her game and she handed the Dane a break with a double fault.
But she knuckled down to see out the tie-break, sealing it with a forehand winner down the line.
"Taking away what she was doing on her side of the net, from my point of view I thought there were just a lot of rollercoaster rides," said the second seed.
"I'd put two or three good points together and then the level sort of dropped, but that's all right. "The good thing is I got a win and can play another match tomorrow."
It was a determined display with plenty of powerful, deep hitting that at times had been lacking against Cibulkova.
It was the second piece of good news for Sharapova on the day as it was also confirmed that she would be the new world number one following Justine Henin's retirement when the WTA rankings are released next week.
She next plays Swiss ninth seed Patty Schnyder, who beat eighth-seeded Frenchwoman Marion Bartoli 6-4, 4-6, 7-6 (9/7) in a marathon battle.
Third seed and last year's runner-up Svetlana Kuznetsova was the big casualty of the day as she lost to French qualifier Alize Cornet.
It was a stunning victory for the 18-year-old who dominated her more illustrious opponent from start to finish in a 6-2, 6-4 success and will now play former world number one Serena Williams.
The American upset Italian hopes as she moved into the quarter-finals at the expense of home favourite Sara Errani.
The former Wimbledon champion won 6-4, 6-3 in a typically dominant performance.
And she said things are looking good for her ahead of the French Open, which starts later this month.
"I'm definitely feeling much fitter than last year or the year before," she said.
Serena is looking to earn her second title here having lifted the trophy in 2002, beating Henin in the final.
Her sister Venus, the seventh seed, played in the late match and beat Russia's 10th seed Vera Zvonareva 7-5, 6-2.
She will next play fourth seeded Serbian Jelena Jankovic, who made short work of Russian Maria Kirilenko, giving up just two games in a 6-1, 6-1 win.
Cornet put her victory over Kuznetsova down as her best ever.
"My best performance until now was against (Agnes) Szavay who was ranked 13th. Now it's against Kuznetsova who is number five (in the world). It's crazy, I'm really happy," said the teenager, who will play Serena.
"After beating Svetlana, why not Serena," said the slender French girl.