U.S. No. 1 Isner out of Australian Open
January 10, 2013 -- Updated 1044 GMT (1844 HKT)
John Isner will miss this month's Australian Open, where he has never been beyond the fourth round.
- U.S. No. 1 John Isner will miss the Australian Open due to a bruised bone in knee
- World No. 13 complained of the injury after his loss to Ryan Harrison in Sydney
- Compatriot Harrison beaten in quarterfinals by Julien Benneteau on Thursday
- World No. 35 Benneteau will now be seeded for Melbourne grand slam in Isner's absence
(CNN) -- The United States' top male tennis player John Isner will miss the Australian Open with a knee injury.
Isner crashed out in the second round of the Sydney International warm-up event -- where he was top seed -- to fellow American Ryan Harrison and complained of a recurrence of the injury which kept him out the recent Hopman Cup tournament in Perth.
"I am extremely disappointed to announce that I have to withdraw from the Australian Open," Isner, who had been seeded 13th for the year's first grand slam, told the ATP Tour's official website on Thursday.
"I have been feeling some discomfort in my knee and have recently learned that I have a bone bruise.
Funny: Open Court outtakes
Clijsters reflects on career, family
Safarova: 'One of my best matches ever'
"My doctors have told me that continuing to play on the knee could result in a more serious injury, so I have regrettably decided not to compete in Melbourne and use the time to fully recover."
Read: Tennis stars feel the heat in Sydney
Isner, a winner of five titles since turning pro in 2007, has never advanced beyond the fourth round of the Melbourne grand slam. He will be replaced in the draw by a lucky loser from one of the qualifying competitions.
The 27-year-old's best performance in one of tennis' four marquee tournaments came in 2010 when he reached the quarterfinals of the U.S. Open.
Harrison chalked up his first ever win over an opponent ranked inside the world's top 15 with his 6-4 6-4 success against Isner on Wednesday, but he lost his quarterfinal match 6-4 6-2 to Frenchman Julien Benneteau.
Benneteau, the 2012 Sydney runner-up, will now be seeded at the Australian Open following Isner's withdrawal.
He will play big-serving Kevin Anderson in the Sydney semifinals after the 36th-ranked South African beat Uzbekistan's Denis Istomin 6-4 6-3.
World No. 35 Benneteau holds a 2-0 winning career record over Anderson and he is confident of extending that in their last four contest.
"He's playing good," said the 31-year-old. "He's a dangerous player with a very big serve but I know I can beat him."
Australia's Bernard Tomic also reached the last four, with the 20-year-old beating veteran Finn Jarkko Nieminen 6-7 (6-8) 6-4 6-2.
He will face either Italian third seed Andreas Seppi or Spanish No. 8 Marcel Granollers.
Part of complete coverage on
December 5, 2013 -- Updated 1517 GMT (2317 HKT)
South Africa may just have found another Paralympian to inspire a nation -- and perhaps the world.
November 26, 2013 -- Updated 1253 GMT (2053 HKT)
Marion Bartoli's tennis career had its ups and downs -- both personal and professional. Discover what has made the Wimbledon winner happy.
November 22, 2013 -- Updated 1654 GMT (0054 HKT)
Maria Sharapova has turned to her third coach of 2013 as she seeks to bounce back from shoulder problems.
November 21, 2013 -- Updated 1158 GMT (1958 HKT)
Hitting partner Sascha Bajin and coach Patrick Mouratoglou offer a glimpse into the life of the world No. 1.
November 29, 2013 -- Updated 1706 GMT (0106 HKT)
Down and out in Paris, Serena Williams turned to a man who has helped her become more dominant than ever before.
November 20, 2013 -- Updated 1003 GMT (1803 HKT)
World Anti-Doping Agency president John Fahey tells CNN he doesn't think Novak Djokovic "has the faintest idea" what his organization does.
The Davis Cup can step up to a new level of popularity by following the example of football's top tournament, says CNN's Will Edmonds.
November 12, 2013 -- Updated 1546 GMT (2346 HKT)
A year that began with a fourth Australian Open title ended similarly triumphant for Novak Djokovic at the ATP Tour finale.
CNN's Will Edmonds says Serena Williams can match Steffi Graf's record haul of 22 grand slam titles following her U.S. Open triumph.
September 9, 2013 -- Updated 1224 GMT (2024 HKT)
Two years after losing part of her lung during a blood clot operation, U.S. Open champion Serena Williams insists playing tennis "is just fun now."
September 4, 2013 -- Updated 1130 GMT (1930 HKT)
Her doubles playing dad is the sporting star of the family, but Micaela Bryan's Twitter page is making the toddler a viral sensation.
Roger Federer is now in danger of diminishing his incredible tennis legacy, says CNN's Will Edmonds.
August 27, 2013 -- Updated 1107 GMT (1907 HKT)
Tennis parents don't have the best of reputations. Think Damir Dokic, John Tomic and Jim Pierce. However, Andy Murray's Mum is very different.
August 15, 2013 -- Updated 1421 GMT (2221 HKT)
Marion Bartoli has retired from tennis with immediate effect, just six weeks after winning her first grand slam title at Wimbledon.
November 19, 2013 -- Updated 1310 GMT (2110 HKT)
When the women's singles champion at the U.S. Open picks up her $2.6 million check, she should spare a moment to thank Billie Jean King.
Today's five most popular stories