Cincinnati

Barty has enjoyed a breakthrough year in 2017, claiming her first WTA Tour title and climbing into the world's top 50 for the first time.

However, prior to Wednesday, the Australian had lost all six of the matches she had played against top-10 opponents.

That winless streak was broken in Cincinnati as Barty overcame a second-set wobble to beat Williams 6-3 2-6 6-2.

"To play Venus on such a big stage is a privilege for me and to play as well as I did, I'm really excited," said Barty.

World number one Murray struggled with the issue prior to his Wimbledon defence and appeared to be suffering the effects when he was beaten in the quarter-finals by Sam Querrey.

The Brit has not played since that match and pulled out of the Rogers Cup, meaning he could well be replaced at the top of the rankings by Rafael Nadal this month.

However, Murray remains hopeful of being in condition to compete at the US Open.