Serena Williams Has Steffi Graf's 22-Slam Record in Sights at Australian Open

Serena Williams begins her quest Monday to equal Steffi Graf's Open-era record of 22 Grand Slam titles battling fitness concerns and with a host of players desperate to dethrone the defending champion. (Novak Djokovic, Serena Williams Top Seeds at Australian Open)

Following a dominant 2015, the world number one is gunning for a seventh Australian crown adamant that she is over the knee problems that hindered her during the latter half of the year and during her Melbourne Park build-up.

She insisted on Saturday she was "120, 130 percent right" as she prepares for a tricky first-round encounter with Italian Camila Giorgi, the highest ranked non-seeded player in the women's draw.

"I've had a really good preparation. I mean, I didn't have the match play that I've wanted to have," said the 34-year-old American.

"But after playing for so many years on tour, I should be able to, you know, focus on that and the fact that I have played a lot of matches. So that's what I'm trying to focus on now."

Her three Grand Slam titles last year in Australia and at Roland Garros and Wimbledon took her within one of Graf's long-time record of 22 and put her three clear of both Chris Evert and Martina Navratilova.

Melbourne Park has been a happy hunting ground. She claimed her first Australian Open title way back in 2003, beating elder sister Venus in the final, and reached her sixth last year when she toppled arch-rival Maria Sharapova.

Williams is in a tough half of the draw with Russia's Sharapova, seeded five, potentially awaiting her in the quarters.

Sharapova, 28, is also lacking match practice after a left forearm problem forced her out of the Brisbane International, but she too said all is now well.

"Yes, I might be rusty, make a few more unforced errors than I would like, but I'm ready to go," said the 28-year-old, who is attempting to win her first title at Melbourne Park since 2008.

She opens her tournament against Japan's Nao Hibino, with temperatures forecast to hit a sizzling 37 Celsius (98.6 Fahrenheit).

Snapping at the heels of the two veterans are world number two Simona Halep and third ranked Garbine Muguruza, who have also had less than ideal preparations with illness or injury affecting their build-up.

Aggressive baseliner Halep, who won titles in Shenzhen, Dubai and Indian Wells last year, is looking for her first Grand Slam crown.

"I think to win a Grand Slam," she said, when asked her what her focus was. "I don't know if it's going to happen this year, but this is my biggest goal."

'No recipe'

Spain's Muguruza, who had a watershed 2015 and made the Wimbledon final, is also targeting her major breakthrough.

The 22-year-old is now under the guidance of coach Sam Sumyk, who helped Victoria Azarenka to the top of the women's game and successive Australian Open titles in 2012 and 2013.

She said the Frenchman had so far not imparted any specific tips on what it would take to land a maiden Grand Slam on the Melbourne Park hardcourts.

"There is no recipe. I mean, I come here as prepared as possible," she said.

Azarenka, now fully fit after two troubled seasons, is one of the form players, having beaten Germany's Angelique Kerber to claim the Brisbane crown.

It was the resurgent Belarusian's first piece of WTA silverware in two-and-a-half years and sent her soaring up the world rankings to 16, a timely confidence boost.

She said she was excited to be injury-free and in with a chance of recapturing her former glories in Melbourne.

"I feel good, I'm feeling excited. I had a pretty good week of practice here," she said ahead of her first-round encounter with Belgian Alison Van Uytvanck.

Among other players, the world numbers four, six and seven -- Agnieszka Radwanska, Petra Kvitova and Angelique Kerber -- have also been struggling with either injury or illness in the lead-up to the opening Grand Slam of the year.