Andy Murray 'proud' to be in Rio as Novak Djokovic chases elusive gold medal

Murray is defending the title he won so brilliantly in London, an achievement he described on Thursday as the biggest of his career ahead of his three grand slam titles.

World number one Djokovic has never won a gold medal and, after he finally landed the French Open earlier this summer, it is the one glaring hole on his CV.

It would certainly not be a surprise if, like two of this year's three grand slam tournaments, the gold came down to a final between the world's top two players.

Their presence and that of Rafael Nadal - albeit undercooked after more than two months out with wrist problems - to some degree saves an event that is missing half of the top 20.

The most obvious absentees, Swiss duo Roger Federer and Stan Wawrinka, are injured but Milos Raonic and Tomas Berdych skipped the Games due to Zika concerns while the likes of Dominic Thiem, Nick Kyrgios, John Isner and Bernard Tomic have also chosen to sit it out.

"Obviously the injuries don't help," said Murray. "If Roger and Stan were both here I think that would be everyone that's won a grand slam in the last 10 years or so.

"That's unfortunate and some people obviously had different concerns about coming here, some of them to do with Zika.

"It is unfortunate. The Olympics in London was very strong and it's a little bit weaker this time around but everyone views things differently. For me the Olympics is the biggest sporting event by far and I'm proud to be here."

Murray will open his title defence on Sunday against Serbian Viktor Troicki, who at 35 is one of the highest-ranked unseeded players but a man the British number one has beaten seven times out of seven.

Djokovic, on the other hand, was handed a nightmare first-round draw against former US Open champion Juan Martin Del Potro, who he lost to in the bronze medal match in London.

Murray is placing equal emphasis in Rio on the doubles competition, where he and brother Jamie are the second seeds and among the gold medal favourites.

They have won only one match in two previous Olympics but showed in their vital Davis Cup wins last year what a potent combination they can be.

"It would obviously be a huge thing to achieve to win a medal," said Murray, who has not played a match since winning his second Wimbledon title a month ago.

"To do it with your brother would be very, very special and I think both of us are really motivated to try to do that. We're both taking it extremely seriously."

The other British man in the singles, Kyle Edmund, faces Australian Jordan Thompson in round one while Colin Fleming and Dom Inglot are in the doubles.

Britain also has a medal hope in the women's singles in the shape of 10th seed Johanna Konta, who was given a kind draw against Liechtenstein's Stephanie Vogt.

Heather Watson plays China's Peng Shuai and will team up with Konta in the doubles.

Serena Williams already has four gold medals - the same tally as sister Venus - and a repeat of her double success in London is far from out of the question.

Serena crushed Maria Sharapova in the singles final four years ago, losing just a single game.

"Sometimes when I look at that match I don't think I've ever played like that before or after," said the 34-year-old, who won her first medal 16 years ago.

"I'm hoping to get to that level again. Maybe it will happen here in Rio but it's a moment I'll never forget."