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Novak Djokovic is in the kind of form that has rivals no less than Rafael Nadal describing it as being close to perfection. Serena Williams has been injured, has hardly played since the U.S. Open and had to withdraw from her only tune-up event ahead of the Australian Open.

The preparations of the reigning champions couldn't be more contrasting in the week leading up to the first Grand Slam tournament of the year.

They have one thing in common, though: they're both favorites to win again, having each won three of the four majors in 2015. Serena Williams has won six Australian titles, Djokovic has won five — neither player has lost a final at Melbourne Park.

At a ceremony preceding the tournament draw on Friday, Williams and Djokovic posed for photos with the Australian Open trophies in front of Rod Laver Arena.

It was only when told they had to hand back the trophies that Djokovic replied, half-jokingly, "What do you mean they're not ours?" His intentions are clear.

In some ways, Williams' condition reflects the state of play in the upper ranks of the women's game. Most players in the top 10 have withdrawn from a tournament or retired from a match in the first two weeks of the season.

Williams played one set at the Hopman Cup, where she was hampered by inflammation in her left knee. No. 2 Simona Halep (Achilles tendon) and Maria Sharapova (left forearm) withdrew from the Brisbane International without playing a match, and No. 3 Garbine Muguruza retired during her first match with an injured foot.

Agnieszka Radwanska (leg) and Petra Kvitova (illness) withdrew from other warmup tournaments and No. 9 Lucie Safarova announced early she wasn't competing in Australia because of a bacterial infection. Angelique Kerber reached the final in Brisbane, where she lost to resurgent two-time Australian Open champion Victoria Azarenka, before withdrawing from Sydney, where Halep returned to action.

Williams and Sharapova have been practicing at Melbourne Park, showing few signs of injury. Williams had a break after her shocking semifinal loss at the U.S. Open cost her a calendar-year Grand Slam, but said she'd started hitting again in October "because I was really missing it."

She said at the Hopman Cup her knee problem was a mere "bump" in the road.

"Everything is actually really well. Feeling really good. Excited about it," she added on Friday. "OK. I'm ready now."

She'd better be, after the draw created a challenging path to another title.

Williams will open against Camila Giorgi of Italy, who finished 2015 at No. 34 and was the highest-ranked player who was not seeded at Melbourne Park, on Monday. She could also meet former No. 1-ranked Caroline Wozniacki in the fourth round and No. 5 Sharapova in the quarterfinals — a rematch of the 2015 final.

Sharapova, the 2008 champion, said her restricted preparation was purely precautionary.

"I think everyone sees the bigger picture," she said. "You want to do what you can to be healthy and be a part of the Grand Slam so sometimes that's a decision you have to make."

The absences left the door ajar for Azarenka to win her first title since 2013, and demonstrate a renewed confidence after two injury-interrupted seasons. The former No. 1-ranked Azarenka was seeded No. 14 and ended up on the bottom half of the draw with No. 2 Halep, No. 3 Muguruza and No. 8 Venus Williams, avoiding Serena Williams and Sharapova.

While much was made of Serena Williams' near miss of the Grand Slam, Djokovic was only one defeat from a perfect Grand Slam season, too. He lost French Open final to Stan Wawrinka and finished 27-1 in Grand Slam play and 82-6 overall in 2015 — four of his six losses were in finals. He opened 2016 with a crushing 6-1, 6-2 over 14-time major winner Nadal in the Qatar Open final.

"I played against a player who did everything perfect," Nadal said. "I know nobody playing tennis like this ever. Since I know this sport, I never saw somebody playing at this level.

"When I say perfect, it's not one thing in particular. It's everything."

Djokovic opens against Chung Hyeon of South Korea, and could meet 2014 U.S. Open finalist Kei Nishikori in the quarterfinals and four-time Australian champion Roger Federer in the semis. No. 2 Andy Murray, who has lost four Australian Open finals including the 2015 edition, is on the bottom half of the draw with Nadal and Warwinka.

Federer, who lost five finals to Djokovic in 2015, said the Qatar Open final score emphasized the difference between the No. 1-ranked player and the rest.

"Yeah, it was a surprise. Between two top guys ... you rarely see blowouts," Federer said. "That Novak wins maybe not so much because he's been on a roll for a while now.

"Of course he's the favorite for the Australian Open."