Andy Murray believes the men’s singles at this month’s Olympics will still be tough to win despite the absence of a number of high-profile players.

World number four Stan Wawrinka was the latest top-name star player to withdraw from the Games, as he continues to struggle with a back injury, while 17-time major winner Roger Federer confirmed his absence from the tournament last week because of a knee problem.

Other top-ten players to miss the Rio showpiece include Milos Raonic and Tomas Berdych, who have both cited the Zika virus as their reason for not competing.

World number two Murray admits it is disappointing that so many of the world’s top players will not be competing in Brazil, but insists the tournament will still be tough to win. “It’s unfortunate with Roger and with Stan.

They’re obviously two guys who are great players and capable of winning at events like this, so it’s a great shame they aren’t here,” said Murray.

“But still it’s a pretty strong field. A lot of the top-20 players are here. It’s unfortunate that a few of the top 10 are missing.”

Murray is the defending Olympic champion, following his success in London four years ago, and he will be looking to win a second gold medal in Brazil, although he has not played a competitive match since his triumph at Wimbledon on July 10.

The Scot has chosen to train rather than play any warm-up events as he looks to continue his fine run of form.