Williams withdraws from Cincinnati and sparks speculation over US Open involvement
Serena Williams' withdrawal from the Cincinnati Masters has provoked question marks over her involvement at the US Open in just two weeks.
The 23-time Grand Slam champion had to retire from the Rogers Cup final against Bianca Andreescu last week due to back problems.
And now a second pull-out has led many to ponder whether or not she will compete in New York - a tournament she has not won since 2014.
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Williams has lost her last three Grand Slam finals and has been seeking a record-equalling 24th since she won the 2017 Australian Open against her sister Venus.
Speaking of Venus, she came through her match against last year's Cincinnati champion Kiki Bertens 6-3 3-6 7-6 (7-4) to advance to the third round.
Elsewhere in Ohio, Maria Sharapova beat Alison Riske to set up a sensational tie with former world number one Ashleigh Barty.