Tokyo: Twice defended Olympic Tennis Champion Andy Murray withdrew from the men’s singles tournament due to muscle injury, the GB team said in a statement.
Murray, 34, will stay in Tokyo to double play with Joe Salisbury.
The couple won the competition opening match on Saturday.
“I was really disappointed because it had to be interesting but the medical staff had advised me against playing on both events, so I have made difficult decisions to withdraw from single and focus on playing double with Joe,” Murray said in a statement.
“The decision to take part in consultation with medical staff in connection with the quad strain,” he added.
Scotland was scratched from the order of the game just hours before he would face Felix auger-aliascime in the first round.
He was replaced in a lottery by Max Purcell Australia.
The three-time grand slam champion Murray was the only player to win two Olympic singles.
He bid on the third consecutive gold after his victory in London 2012 and Rio 2016.
Murray’s career has been tiring by injury in recent years, twice undergoing hip surgery since increasing to number one world at the end of 2016.
He recently suffered earliest , Wimbledon’s exit in 16 years when he was eliminated in the third round by Canada Denis Shapovalov.
Murray and Salisbury will play Germany Team Puetz and Kevin KrawiTz for a place in the quarter-finals of the double-doubled Olympics after removing the two French seeds Pierre-Hugues Herbert and Nicolas Mahut in the first round.