Even though Justine Henin-Hardenne, Kim Clijsters and Jennifer Capriati are all missing from the Melbourne field, Williams is seeded only seventh for the year's first Grand Slam event, having slid down the rankings in 2004.
The 23-year-old American was unable to defend her 2003 title at last year's event as she recovered from knee surgery but such is her reputation that she is rated as the bookmakers' favourite.
Others argue that world number one Lindsay Davenport and the three Russian grand slam champions, Anastasia Myskina, Maria Sharapova and Svetlana Kuznetsova, have greater claims on the title.
Williams's last Grand Slam victory came 18 months ago at Wimbledon, and her form and fitness since returning to the tour in Miami last March after an eight-month layoff have been inconsistent.
But after a strong finish to 2004, including a runner's-up place at the WTA Tour Championships, the American arrived in Melbourne in ebullient mood, declaring herself ready to regain the form that helped her to secure the 'Serena Slam' of four consecutive grand slam titles in 2002/2003.
DISAPPOINTING DEFEATS
"Anything's possible," said Williams, who was world number one in 2002. "I am really, really excited about this year and very happy to be back in Melbourne."
"I think (being world number one) is probably everyone's aim at the start of the year and it's definitely a goal of mine."
Though she won her first event back after surgery last March, Williams suffered disappointing quarter-final defeats at the French and U.S. Opens and was upset by Sharapova in the final at Wimbledon.
The Australian Open, she said, offered her a great chance for a return to winning ways.
"I love the surface of these courts because it's so bouncy and makes me look so fast," she said. "I know I'll do really well here. I just can't wait to enjoy myself."
The Russian revolution which swept through women's tennis has increased the depth of the women's game, however, and Williams said her rivals were forcing her to improve.
"I think, when everyone plays me, they all try their hardest," she said. "They see me on the court and want to win as much as possible so everyone is a rival to me."
