Andy Murray holds his gold medal after winning the men's singles tennis gold medal during the London 2012 Olympic Games. File Photo: Stefan Wermuth

Rio de Janeiro - Gold medallists from London 2012 Andy Murray and Serena Williams are less than a week away from beginning their title defences at the 2016 Olympics in Rio.

The Olympic Tennis event, which will be held at the newly-constructed Olympic Tennis Centre, gets underway this Saturday, with a record 56 countries represented among the entries in this year's event.

The draw will be held on Thursday. Murray and Williams come to Rio in fine form, with both having secured a first Grand Slam title of 2016 at Wimbledon last month.

Williams will also look to defend her women's doubles title alongside elder sister Venus, an event that the American sisters have won on three occasions. In the men's draw, world No 1 Novak Djokovic will be looking to claim gold for the first time, the Serb won a bronze medal in Beijing in 2008 and finished fourth in London four years ago.

After a hugely surprising defeat in the third round at Wimbledon, Djokovic returned to a form with a win at the Rogers Cup in Toronto on Sunday, and will certainly prove a serious challenge to Murray should the two meet in the final.

Switzerland's Stan Wawrinka and Japan's Kei Nishikori will also be looking to be among the medals in Rio, while 14-time Grand Slam champion and 2008 gold medallist Rafael Nadal will play for the first time since withdrawing from Roland Garros with a wrist injury earlier this year.

While Williams undoubtedly starts the tournament as a heavy favourite to defend her women's singles title, she will recognise the threat posed by the likes of Angelique Kerber and Garbine Muguruza, both of whom have beaten the world No1 in Major finals this year. Sixty-four players will contest both the men's and women's singles.

Entries for both events are a combination of 56 direct acceptances based on the singles world rankings of June 6, and six ITF Places (Final Qualification Places) allocated according to the Qualification System.

There are also two Tripartite Commission Invitation Places. Thirty-two teams will contest both the men's and women's doubles, with entries a combination of 24 direct acceptances and eight ITF Places (Final Qualification Places).

Entries are based on the combined world rankings of each team on June 6, with each player using the better of their singles and doubles world ranking. Any player ranked in the doubles Top 10 on June 6 was eligible for direct acceptance with a partner of any ranking. There is a limit of four singles players per gender per country.

Nations were also able to nominate up to two doubles teams per event, with a maximum of six players per gender per country in total. Entries are also subject to players being in good standing with their National Association and meeting the minimum participation requirements in Davis Cup and Fed Cup.

Entries for the 16-team mixed doubles event will be determined on site from those players already participating in singles or doubles, with a maximum of two teams per country. Teams have to be nominated by their National Olympic Committee by the deadline of 9 August.

The Olympic Tennis Event will be played on hard court, with ten match courts and six practice courts, including a 10 000-capacity centre court, and two additional show courts seating 5 000 and 3 000 spectators respectively.

Tennis was a part of the first modern Olympic Games in 1896. The first woman to win an Olympic medal in any sport was tennis player Charlotte Cooper (GBR) at the 1900 Olympic Games in Paris.

After the 1924 Paris Games, tennis withdrew from the Olympics but returned as a demonstration event at 1984 Los Angeles and as a full medal sport at 1988 Seoul.