MELBOURNE—Wimbledon champion Elena Rybakina eliminated No. 1-ranked Iga Swiatek in straight sets Sunday to reach the Australian Open quarterfinals for the first time. The 22nd-seeded Rybakina used her big serving to unsettle Swiatek and got the better of their baseline exchanges to win, 6-4, 6-4, in about and -and-a-half hours. Swiatek is a three-time…