The 18-time Grand Slam champion last won the Australian Open in 2010 and is targeting winning her sixth crown in Melbourne starting on Monday.
Williams told media on Saturday that her determination to win was stronger than any other player in the 128-strong field.
"I've been going for number six for a number of years now – it would be really special for me, I'd be really happy," said Williams.
"I want it, I think, more than anyone else here. That doesn't mean I'm going to get it so I'll have to fight hard to get it," she added.
Should the 33-year-old American win the Australian crown it would take her to clear second on the all-time Grand Slam winners list behind Steffi Graf's 22.
Williams plays Alison Van Uytvanck of Belgium in the opening round and could face US Open finalist Caroline Wozniacki in the quarter-final.