Jessica Pegula of the United States upset World No. 1 Iga Swiatek on Saturday before wet weather left the American waiting to discover the identity of her WTA Montreal Open final opponent. 

Fourth-seed Pegula took advantage of an error-strewn display by Poland’s Swiatek to complete a 6-2, 6-7 (4/7), 6-4 victory in 2hrs, 30min. But heavy rain over the Montreal region washed out Saturday’s second semi-final between third seed Elena Rybakina of Kazakhstan and 15th seed Liudmila Samsonova.