Bernard Tomic faces a tough task against Kei Nishikori in the Olympics first round, but Lleyton Hewitt has a more favourable draw against Russia's Sergei Stakhovsky.
Tomic, who has dropped to 45 in the world rankings, takes on the Australian Open quarter-finalist first up, with a meeting against world number five David Ferrer likely for the third round.
Hewitt could set up another clash with Novak Djokovic if he can get past Stakhovsky and then a potential tricky second-round clash with Marin Cilic or Jurgen Melzer.
Elsewhere, Roger Federer has been the biggest beneficiary of Rafa Nadal's withdrawal from the Olympics, as Novak Djokovic and Andy Murray are on the opposite side of the draw.
The Swiss maestro, playing on his favourite surface at Wimbledon, looks to have a fairly easy route to the semi-final where he is likely to meet either David Ferrer or Juan Martin del Potro.
In the opening round he faces Colombia's Alejandro Falla, who was two sets up against Federer before falling to defeat in their Wimbledon first-round clash in 2010.
Serbia's Novak Djokovic, seeded two, will take on Italy's Fabio Fognini, referee Stefan Fransson said, unveiling the draw in a lounge at Wimbledon's centre court adorned with large photos of London landmarks including Buckingham Palace and the London Eye.
Before a potential meeting with Djokovic, third-seed Murray will have to beat Federer's fellow-Swiss Stanislas Wawrinka in his opening match, an announcement which drew a noisy response from a room packed with team leaders, officials and media.
Murray has won six of the ten times the pair have met previously.
Women's top seed Belarusian Victoria Azarenka will play Romanian world number 79 Irina-Camelia Begu in the first round, while America's Serena Williams, fresh from her fifth Wimbledon title, takes on former world number one Jelena Jankovic of Serbia.
Neither of Beijing's singles gold medallists will be returning to defend their titles, after Spain's Rafa Nadal was forced to pull out through injury and Russia's Elena Dementieva retired. But the draw is the strongest ever, with 18 of the world's top 20 men and 19 of the top 20 women taking part.
Top-seeded men's duo Mike and Bob Bryan, who won bronze in Beijing, will begin their medal campaign by playing Brazil's Thomaz Bellucci and Andre Sa, and could face defending doubles gold medallists Federer and Wawrinka in the quarter-finals.
In the women's doubles, top seeded American's Liezel Huber and Lisa Raymond get a pass to the second round after the withdrawal of Ukraine's Alona and Kateryna Bondarenko due to injury.
Unseeded defending gold medallists Venus and Serena Williams will take on Romania's Sorana Cirstea and Simona Halep.
ABC/ReutersTags: sport, tennis, olympics-summer, united-kingdom, australia First posted July 27, 2012 11:07:19