Serena Williams has withdrawn from the Miami Open due to a left knee injury.
The eight-time champion was forced to hand a walkover to China’s Wang Qiang in the third round of the tournament.
It's the second consecutive WTA event the 37-year-old Serena has had to withdraw from.
She recently retired from the tournament in Indian Wells due to a viral illness.
Serena is yet to win a title since returning from maternity leave last year.