Tennis: Champions Murray, Serena in Sunday special

Andy Murray of Great Britain plays a forehand during a proactice session on Day Six of the 2013 US Open at USTA Billie Jean King National Tennis Center on Aug 31, 2013 in the Flushing neighborhood of the Queens borough of New York City. Defending cha
Andy Murray of Great Britain plays a forehand during a proactice session on Day Six of the 2013 US Open at USTA Billie Jean King National Tennis Center on Aug 31, 2013 in the Flushing neighborhood of the Queens borough of New York City. Defending champions Murray and Serena Williams as well as Novak Djokovic are the Sunday special acts at the US Open while former title winner Lleyton Hewitt looks to continue his dream run. -- PHOTO: AFP

NEW YORK (AFP) - Defending champions Andy Murray and Serena Williams as well as Novak Djokovic are the Sunday special acts at the US Open while former title winner Lleyton Hewitt looks to continue his dream run.

Third seed Murray, who is also the Olympic and Wimbledon champion, disposed of Leonardo Mayer in the second round and now faces another Mayer - Germany's Florian Mayer - for a place in the fourth round.

Murray has a 2-0 career lead over the 29-year-old German, winning their most recent meeting in two tiebreak sets on the Madrid clay earlier this year.

Mayer, the world number 47, has twice been a Wimbledon quarter-finalist in 2004 and 2012 but has never got beyond the third round in New York.

World number one Williams will have the chance to avenge her exit from the Australian Open when she faces compatriot Sloane Stephens for a quarter-final spot.

Williams' relationship with Stephens was strained after her younger rival upset the 16-time Grand Slam champion at Melbourne.

"It's going to be tough," Williams said. "Sloane is playing so well. I'm always so happy for her. She's doing great. I'm really proud of Sloane. It's going to be a really good match." American 15th seed Stephens faces the superstar she accused of disrespectful intimidation tactics and mind games in Australia.

"It'll be epic and something a lot of people will be looking forward to," Stephens said. "I'm excited about it." Williams, who at 31 could become the oldest US Open women's winner, and Stephens have not played since the 20-year-old beat the four-time US Open champion in the Australian Open quarter-finals.

Stephens was friendly with Williams a year ago at New York but the relationship soured after Williams beat her in a Brisbane quarter-final 6-4, 6-3 and then suffered the shock Grand Slam defeat.

Top seed in the men's event, Novak Djokovic, the 2011 champion, takes on unseeded Portuguese player Joao Sousa.

Tommy Haas, the German 12th seed and, at 35, the oldest man in the tournament, tackles Russia's Mikhail Youzhny.

A victory could pit Haas against Hewitt, the 2001 champion, in the fourth round.

The Australian stunned sixth seed and 2009 champion Juan Martin Del Potro in the second round for his first win over a top 10 player in New York since his victory over Pete Sampras in the 2001 final.

Order of play on main courts at (x denotes seeded player):

Arthur Ashe Stadium (1100 local time; 1500 GMT) Bob Bryan/Mike Bryan (USA/USA x1) v Daniel Nestor/Vasek Pospisil (CAN/CAN) Andy Murray (GBR x3) v Florian Mayer (GER) Serena Williams (USA x1) v Sloane Stephens (USA x15)

1900 local time/2300 GMT Novak Djokovic (SRB x1) v Joao Sousa (POR) Jelena Jankovic (SRB x9) v Li Na (CHN x5)

Louis Armstrong Stadium (1100 local time; 1500 GMT) Stanislas Wawrinka (SUI x9) v Marcos Baghdatis (CYP) Carla Suarez Navarro (ESP x18) v Angelique Kerber (GER x8) Tommy Haas (GER x12) v Mikhail Youzhny (RUS x21)

Grandstand (1100 local time; 1500 GMT) Julien Benneteau (FRA x31) v Tomas Berdych (CZE x5) Tim Smyczek (USA) v Marcel Granollers (ESP) Agnieszka Radwanska (POL x3) v Ekaterina Makarova (RUS x24)