(CNN) -- World No. 1 Serena Williams' preparations for her Australian Open title defense suffered a late blip when she was beaten in the final of the Sydney International by Elena Dementieva on Friday.
The American, who had struggled past unseeded Frenchwoman Aravane Rezai in three sets in the semifinals when she appeared to injure her left leg, lost 6-3 6-2 to suffer her fifth defeat in her last eight clashes with the Russian.
"I was struggling a little bit, but she definitely deserves all the credit," Williams told reporters. "It's definitely not ligament problems. It's just a little pain but the strapping usually helps the pain go away."
Dementieva, who beat world No. 2 Dinara Safina in the quarterfinals, successfully defended her title in the final event before the first Grand Slam tournament of this decade starts on Monday.
"It's great to play against the best players in the world, especially going into a Grand Slam. It was a great experience and it'll help me next week at the Australian Open," she told the WTA Tour's official Web site
Dementieva went into the match against Williams having been handed a potential second-round clash with former world No. 1 Justine Henin, who pulled out of the Sydney event as a precaution after suffering a leg injury in her comeback tournament in Brisbane.
Seven-time Grand Slam winner Henin, handed a wildcard after a 20-month retirement, will start against unseeded fellow Belgian Kirsten Flipkens on Monday while fifth seed Dementieva plays fellow Russian Vera Dushevina .
Both have avoided the Williams sisters, who are in the top half of the draw with Serena opening against Poland's Urszula Radwanska on Tuesday and sixth seed Venus taking on Czech Lucie Safarova.
Four-time winner Serena could face seventh seed Victoria Azarenka in the last eight, with a possible semifinal against her older sibling looming.
Last year's losing finalist Safina opens against world No. 44 Magdalena Rybarikova of Slovakia, and could face fellow Russian Maria Sharapova in the fourth round.
Sharapova, the 2008 champion but seeded 14th after struggling with shoulder problems last year, begins with a glamour clash against compatriot and fellow pin-up girl Maria Kirilenko.
U.S. Open champion Kim Clijsters could face fellow comeback queen Henin in the quarterfinals, having been seeded 15th and facing a qualifier first up.
But to set up a rematch of the recent final in Brisbane, which she won, Clijsters is likely to have to overcome third seed Svetlana Kuznetsova in the fourth round.
The Russian, who has never got past the last eight in Melbourne, takes on unseeded compatriot Anastasia Rodionova in her first match.
Australian Open women's singles draw (seeds in bold):
1-Serena Williams (USA) v Urszula Radwanska (Pol)
Petra Kvitova (Cze) v Jill Craybas (USA)
Qualifier v Andrea Petkovic (Ger)
Ayumi Morita (Jpn) v 32-Carla Suarez-Navarro (Spa)
21-Sabine Lisicki (Ger) v Petra Martic (Cro)
Varvara Lepchenko (USA) v Alberta Brianti (Ita)
Kristina Barrois (Ger) v Akgul Amanmuradova (Uzb)
Qualifier v Samantha Stosur (Aus) (13)
9-Vera Zvonareva (Rus) v Kristina Kucova (Svk)
Kai Chen Chang (Tpe) v Iveta Benesova (Cze)
Qualifier v Gisela Dulko (Arg)
Qualifier v 20-Ana Ivanovic (Ser)
28-Elena Vesnina (Rus) v Tathiana Garbin (Ita)
Kimiko Date Krumm (Jpn) v Yaroslava Shvedova (Kaz)
Stefanie Voegele (Swi) v Melinda Czink (Hun)
Stephanie Cohen Aloro (Fra) v 7-Victoria Azarenka (Blr)
4-Caroline Wozniacki (Den) v Aleksandra Wozniak (Can)
Tamira Paszek (Aut) v Julia Goerges (Ger)
Galina Voskoboeva (Kaz) v Tsvetana Pironkova (Bul)
Lucie Hradecka (Cze) v 29-Shahar Peer (Isr)
22-Daniela Hantuchova (Svk) v Viktoriya Kutuzova (Ukr)
Jarmila Groth (Svk) v Qualifier
Stephanie Dubois (Can) v Agnes Szavay (Hun)
Marina Erakovic (Nzl) v 16-Na Li (Chn)
10-Agnieszka Radwanska (Pol) v Tatjana Malek (Ger)
Melanie Oudin (USA) v Alla Kudryavtseva (Rus)
Julie Coin (Fra) v Alicia Molik (Aus)
Alize Cornet (Fra) v 17-Francesca Schiavone (Ita)
25-Anabel Medina Garrigues (Spa) v Karolina Sprem (Cro)
Anastasiya Yakimova (Blr) v Casey Dellacqua (Aus)
Arantxa Parra Santonja (Spa) v Sybille Bammer (Aut)
Lucie Safarova (Cze) v 6-Venus Williams (USA)
5-Elena Dementieva (Rus) v Vera Dushevina (Rus)
Kirsten Flipkens (Bel) v Justine Henin (Bel)
Sorana-Mihaela Cirstea (Rom) v Olivia Rogowska (Aus)
Jelena Dokic (Aus) v 27-Alisa Kleybanova (Rus)
18-Virginie Razzano (Fra) v Ekaterina Makarova (Rus)
Klara Zakopalova (Cze) v Sara Errani (Ita)
Qualifier v Alexandra Dulgheru (Rom)
Anna Chakvetadze (Rus) v 12-Flavia Pennetta (Ita)
15-Kim Clijsters (Bel) v Qualifier
Sesil Karatantcheva (Kaz) v Tamarine Tanasugarn (Tha)
Yung-Jan Chan (Tpe) v Kaia Kanepi (Est)
Edina Gallovits (Rom) v 19-Nadia Petrova (Rus)
26-Aravane Rezai (Fra) v Sania Mirza (Ind)
Olga Govortsova (Blr) v Qualifier
Anastasia Pavlyuchenkova (Rus) v Anastasija Sevastova (Lat)
Anastasia Rodionova (Rus) v 3-Svetlana Kuznetsova (Rus)
8-Jelena Jankovic (Ser) v Monica Niculescu (Rom)
Patricia Mayr (Aut) v Katie O'Brien (GB)
Qualifier v Polona Hercog (Slo)
Qualifier v 31-Alona Bondarenko (Ukr)
24-Maria Jose Martinez Sanchez (Spa) v Evgeniya Rodina (Rus)
Jie Zheng (Chn) v Shuai Peng (Chn)
Coco Vandeweghe (USA) v Sandra Zahlavova (Cze)
Rossana De los Rios (Par) v 11-Marion Bartoli (Fra)
14-Maria Sharapova (Rus) v Maria Kirilenko (Rus)
Qualifier v Timea Bacsinszky (Swi)
Anna-Lena Groenefeld (Ger) v Roberta Vinci (Ita)
Vania King (USA) v 23-Dominika Cibulkova (Svk)
30-Kateryna Bondarenko (Ukr) v Ioana Raluca Olaru (Rom)
Pauline Parmentier (Fra) v Elena Baltacha (GB)
Barbora Zahlavova-Strycova (Cze) v Qualifier
Magdalena Rybarikova (Svk) v Dinara Safina (Rus) (2)