"I came to Mason on Sunday and have tried everything to be ready to play. But unfortunately my back is still not right and I know I should not take to the court."
Wednesday 14 August 2019 14:29, UK
Serena Williams has withdrawn from the Cincinnati Masters with the same back injury that forced her to retire from the Rogers Cup final.
The two-time winner of the tournament said she was "hopeful" after her practice on Tuesday morning but eventually decided that playing would not be possible.
The back injury caused her to retire from the final in Toronto at 3-1 down and with the US Open starting on August 26, a close eye will be kept on further updates from the 23-time Grand Slam winner.
"I really want to thank tournament director Andre Silva and the WTA for giving me every chance to play," said Williams to the WTA after announcing her decision.
"I also want to thank all the amazing fans here in the Cincinnati area for their support - it means so much. I promise I'll do my best to be back here next year."
Williams' place in the main draw was taken by lucky loser Jessica Pegula. The American faced her original first-round opponent Zarina Diyas and fell in straight sets 7-5 6-4.
In contrast to Serena's injury problems, older sister Venus Williams sent shockwaves around the women's draw with a 6-3 3-6 7-6 (7-4) victory over the defending champion Kiki Bertens.
The two-hour-and-17-minute clash was the 39-year-old's second victory over a top-five player this season and she'll now meet either Donna Vekic or Victoria Azarenka in the Round of 16.
I just tried not to go too big, because I can go so big and I have a lot of power and it's not always easy to control it. So I'm trying to play smart instead of going hog wild, which is extremely easy to do.
Elsewhere in the draw, Angelique Kerber followed Britain's Johanna Konta in falling at the first hurdle and being knocked out in the opening round.
Kerber, the 13th seed, was undone by the determined work of Anett Kontaveit. The German did open out to a 5-3 lead in the first set, and had a set point opportunity at 6-5, before she narrowly lost the tie-break.
At the beginning of the second, Kontaveit then put her foot on the gas to produce a 4-0 lead. Despite being broken once, she finished the job in style and will now face qualifier Iga Swiatek in the second round.
Madison Keys and Garbine Muguruza, the 2017 champion, were embroiled in one of the tightest matches of the day as they met in the opening round for the second year in a row.
Keys arrived at the encounter having lost in the first round in Washington and at the Rogers Cup but showed great determination to prevent that happening for a third time with the 6-7 (7-4) 7-6 (7-5) 6-4 result.
Under the evening lights, Maria Sakkari overcame being down a break in the deciding set to prevail 6-4 2-6 6-3 over Petra Kvitova.
Sakkari kept her composure to captalise on Kvitova's mistakes as the Czech player put down 53 unforced errors during the course of the match.
Wednesday's order of play is an action-packed one and one that features a hotly-anticipated clash between Ashleigh Barty and Maria Sharapova.
The two players have a career head-to-head record of one victory apiece, the last match being secured by Barty at this year's Australia Open.
Sharapova is one of three former tournament champions in action on Wednesday.
Karolina Pliskova is another and she'll meet the lucky loser Wang Yafa. The 2013 winner, Azarenka will take on Vekic on Court 10.
