Pegula dispatched her compatriot Krueger 6-4, 2-0 through retirement, while Paul sealed his berth in the final-four in Adelaide with a 6-3, 6-4 victory over Australian Hijikata.
Sinner upset Djokovic in the semifinals here last year before coming back to beat Daniil Medvedev in the final 3-6, 3-6, 6-4, ...