MELBOURNE - Defending champion Stan Wawrinka was Friday pitted in the top half of the draw at the Australian Open with Novak Djokovic and faces a potential semi-final encounter with the world number one. The Swiss fourth seed upset Djokovic in the quarter-finals on the way to winning his first Grand Slam title in Melbourne last year.

The Serb top seed is scheduled to face big-serving Canadian Milos Raonic in the quarters, while Wawrinka could meet Japanese fifth seed Kei Nishikori in the last eight. "It changes everything in your career, for sure," Wawrinka said of his life-changing Grand Slam triumph. "When you win a Grand Slam you really start to be a part of the history of tennis. It changed my life and my tennis. I feel good and happy to be back. I'm playing well and have confidence in my game. It's the first Grand Slam of the year, everything starts from zero again, and you have to be ready for the two weeks," he added.

Roger Federer, who is chasing an 18th Grand Slam victory at the age of 33, is on course to face Andy Murray in the quarter-finals in the bottom half of the draw. Murray, a three-time Australian Open runner-up, lost to the Swiss great in the 2010 Melbourne Park final. Federer, who will face Taipei's Lu Yen-Hsun in the opening round, is the second seed. Third seed Rafael Nadal faces a tough first-up opponent in Russian Mikhail Youzhny and could play big-serving Czech Tomas Berdych in the quarters in the bottom half of the draw.

One of the tougher first-round match-ups will see 2009 US Open champion Juan Martin del Potro, who is on the comeback trail from wrist surgery, take on Poland's Jerzy Janowicz. Australian warhorse Lleyton Hewitt, playing in his 19th consecutive Australian Open, has drawn Chinese wildcard Zhang Ze in the opening round.

Serena seeded to face Wozniacki in Open quarters: World number one Serena Williams faces a potential rematch of her US Open final against Caroline Wozniacki in the quarter-finals of the Australian Open following Friday's draw. Williams, who is chasing her 19th Grand Slam title in Melbourne, beat Wozniacki in straight sets in New York last year. The American meets Belgian Alison van Uytvanck in the first round, while second seed Maria Sharapova first faces a qualifier in the tournament beginning on Monday.

Fourth seed and two-time Wimbledon champion Petra Kvitova, who is playing in the Sydney International final later Friday, is seeded to face Agnieszka Radwanska in the other quarter-final in the top half of the draw. Sharapova is projected to face rising Canadian Eugenie Bouchard, while third seed Simona Halep could meet Ana Ivanovic in the other last eight clash in the bottom half of the women's draw.

The most interesting first-round match up will be between two-time Australian Open champion but unseeded Victoria Azarenka and American Sloane Stephens, a semi-finalist in Melbourne two years ago.