Undated, Mar 8 (REUTERS) Serena Williams has withdrawn from the BNP Paribas Open in Indian Wells and the Miami Open due to a left knee injury and as a result will relinquish the world number one tennis ranking to German Angelique Kerber.
Williams, a two-times champion at the showpiece event at the California desert resort, had returned to the women's top ranking in January after claiming a record 23rd grand slam singles title in the professional era at the Australian Open.