Two-time defending Olympic tennis champion Andy Murray withdrew Sunday from the men's singles tournament due to a muscle injury, Team GB said in a statement.

Murray, 34, will stay in Tokyo to play doubles with Joe Salisbury. The pair won their opening match of the competition on Saturday.

"I am really disappointed at having to withdraw but the medical staff have advised me against playing in both events, so I have made the difficult decision to withdraw from the singles and focus on playing doubles with Joe," Murray said in a statement.

"The decision follows consultation with medical staff in relation to a quad strain," it added.

The Scot was scratched from the order of play just hours before he was due to face Canada's Felix Auger-Aliassime in the first round. He was replaced in the draw by Australia's Max Purcell.

Three-time Grand Slam champion Murray is the only player to win two Olympics singles titles. He was bidding for a third successive gold following his victories at London 2012 and Rio 2016.

Murray's career has been blighted by injury in recent years, twice undergoing hip surgery since rising to world number one at the end of 2016.

He recently suffered his earliest Wimbledon exit in 16 years when he was knocked out in the third round by Canada's Denis Shapovalov.

Murray and Salisbury will play Germany's Tim Puetz and Kevin Krawietz for a spot in the Olympic men's doubles quarter-finals after dumping out French second seeds Pierre-Hugues Herbert and Nicolas Mahut in the first round.