• American not played since picking up injury at Wimbledon
• Williams, 40 next month, is still seeking elusive 24th slam
Serena Williams has withdrawn from the US Open, marking another major setback in an extremely difficult season.
Williams, who turns 40 next month, has not competed since she was forced to withdraw from her first round match at Wimbledon after falling on the slippery grass courts against Aliaksandra Sasnovich, tearing her right hamstring and then leaving the court in tears.
Related: Emma Raducanu ‘zoning out on the road’ after her eye-catching Wimbledon