She decided also to miss the Miami Open later this month even if she is more or less a hometown favorite. “I have not been able to train due to my knees,” she said. Her withdrawal means Germany’s Angelique Kerber is set to replace her as world number one. Williams only returned to the Californian tournament in 2015 after a 14-year boycott following claims she had suffered racist abuse at the venue. Last year, Serena looked strong through the tournament but has not won, losing the final to Victoria Azarenka (6-4, 6-4). Serena, who resides in Palm Beach Gardens, Florida, has won Miami eight times. She has 23 Grand Slam singles titles and is probably the greatest singles player of all time. Now, she promised to return.