Novak Djokovic has overcome some trouble breathing and played quite well for a straight-set victory over 26th-seeded Tomas Machac to reach the fourth round at the Australian Open.

Novak Djokovic and Andy Murray faced each other 36 times throughout their tennis careers, mostly in finals and often at the business end of a grand slam. But at this year’s Australian Open, their decades-long rivalry has taken an unexpected turn.