India, Jan. 26 -- Defending champion Madison Keys' Australian Open title defence came to a swift end on Sunday as she fell to good friend and podcast co-host Jessica Pegula in the fourth round. Pegula produced a clinical, no-nonsense show on Rod Laver Arena to secure a straight-sets 6-3, 6-4 victory, never allowing her compatriot to settle into her rhythm.

Pegula will play either another American, the fourth seed Amanda Anisimova, or China's unseeded Wang Xinyu in the quarterfinal.

Also in the women's draw in the fourth round, fifth seed Elena Rybakina plays 21st seed Elise Mertens and second seed Iga Swiatek will be heavy favourite against Maddison Inglis.

The Australian qualifier, ranked 168, who will feature on Rod Laver Arena in th...