Britain's Andy Murray is to face a tricky opponent in the first round of the Olympic tennis tournament at Wimbledon after being drawn against Swiss Stanislas Wawrinka Thursday.
Murray has lost four of his 10 previous matches against the Swiss No. 2, and their only previous meeting at Wimbledon went to five sets in 2009.
Wawrinka is also a reigning Olympic champion after winning the men's doubles for Switzerland in 2008 alongside Roger Federer.
World No.1 Federer has been handed a first-round match with Columbia's Alejandro Falla, the world No.51, while second-ranked Novak Djokovic faces Italy's Fabio Fognini, the world No.67.
Djokovic has the toughest potential quarterfinal opponent, as he is in the same section of the draw as world No.5 Jo-Wilfried Tsonga of France.
Djokovic and Murray can meet in the semi-finals, while Federer can meet David Ferrer, who was seeded fourth after his fellow Spaniard Rafael Nadal withdrew through injury.
In the women's draw, the Williams sisters look set to feature in the first round's high-profile matches, with Serena Williams taking on former world No.1 Jelena Jankovic, and Venus Williams facing French Open finalist Sara Errani, the ninth seed.
Both Williams sisters are in the same half of the draw as world No.1 Victoria Azarenka, who has been handed a relatively easy first-round match with Romanian world No.79 Irina-Camelia Begu.
Russia's world No.3 Maria Sharapova takes on 49th-ranked Shahar Peer of Israel in the first-round, and could meet second seed Agnieszka Radwanska of Poland in the semi-finals.
The Pole has a potentially tricky first-round tie against world No.24 Julia Goerges, although Radwanska has won both of their previous meetings