Serena Williams insists she is fit and ready in her quest for back-to-back Australian Open titles.

Williams, 34, has had limited preparation for the Australian Open, where she will meet unseeded Italian Camila Giorgi in the first round, with the world number one hampered by a knee injury.

The 21-time grand slam champion - a six-time winner at Melbourne Park - retired hurt against Jarmila Wolfe at the Hopman Cup on January 6.

Williams was asked about her troublesome knee at the Australian Open draw on Friday and said: "It's actually very well. I'm feeling really good and I'm excited about it.

"I've been training every day for so long and I'm like, 'OK, I'm ready now' so it feels good."

Williams, who has only lost nine matches at the Australian Open since debuting in 2003, will come up against the highest ranked unseeded player in the draw at 35 in the WTA Tour.

If Williams makes it through the opening round, world number five Maria Sharapova looms as a potential quarter-final opponent in a rematch of last year's decider.