Pakistan, Sept. 19 -- Newly crowned world number one Elena Rybakina will miss the Billie Jean King Cup Finals for Kazakhstan, the US Open champion said on Friday, citing a physically demanding month. The 27-year-old produced a dominant performance to dethrone two-time defending champion Aryna Sabalenka in last weekend's US Open final, securing a third Grand Slam title to go with her rise to the top of the rankings. An ankle injury had threatened to derail Rybakina's campaign before the tournament began, but she overcame those concerns to add the US Open crown to her Australian Open title this year and her 2022 Wimbledon triumph. "I have to announce that I won't be able to participate in Billie Jean King Cup this year," Rybakina wrote on I...