The World No. 1, despite feeling unwell in sweltering conditions, kept up his title defense with a four-set triumph.

World No.1 and defending champion Jannik Sinner, Iga Swiatek, Elina Svitolina, Elena Rybakina and other big players will be in action on Day 9 of the hard court major at the Melbourne Park.

Novak Djokovic was at the centre of another Australian Open row on Monday while Jannik Sinner needed medical attention in fierce heat to battle into the quarter-finals and Iga Swiatek won easily. But American teenage qualifier Learner Tien’s fairytale run is over after he suffered a thigh problem in a four-set defeat to Italy’s Lorenzo Sonego in Melbourne.

Defending champion Jannik Sinner moved into the Australian Open quarterfinals at Melbourne Park on Monday by eliminating the 13th-seeded Holger Rune 6-3, 3-6, 6-3, 6-2.