Serena Williams will lose her world number one ranking to Angelique Kerber after pulling out of the BNP Paribas Open in Indian Wells.
The 35-year-old announced on Tuesday – the eve of the tournament – that an injury to her left knee had forced her to withdraw from both from the Californian tournament and the Miami Open, which takes place in her home state of Florida later this month.
Williams, who made the final in Indian Wells 12 months ago, will now lose all of those ranking points and hand the top ranking back to Kerber on March 20.
The Australian Open champion said in a statement: “Sadly, I have to withdraw from the BNP Paribas Open in Indian Wells and the Miami Open.
“"I have not been able to train due to my knees and am disappointed I cannot be there. I will keep moving forward and continue to be positive. I look forward to being back as soon as I can."
The draw has been reshuffled with third seed Karolina Pliskova taking Williams’ place at the top of the draw. Pliskova’s slot is filled by fifth seed Dominika Cibulkova.
The projected quarter-finals are now:
(3) Karolina Pliskova v (7) Garbine Muguruza
(5) Dominika Cibulkova v (8) Svetlana Kuznetsova
(9) Madison Keys v (4) Simona Halep
(6) Agnieszka Radwanska v (2) Angelique Kerber