Samantha Stosur and Ash Barty's doubles teams will carry all of Australia's Olympic tennis medal hopes after James Duckworth was the last to be eliminated from singles.

Heavy rain meant Duckworth was made to wait to begin his second-round match against Russian heavyweight Karen Khachanov.

He pushed the favourite early before bowing out in a 7-5 6-1 loss in 88 minutes.

Attention now turns to Australia's two women's doubles pairings.

Barty and long-time friend Storm Sanders have made the quarter-finals, as have five-time Olympian Stosur and Ellen Perez.

Their opponents are yet to be decided, but they're at opposite ends of the draw, ensuring they couldn't meet until the gold medal match.