Djokovic battles into last eight

Novak Djokovic ensured seven of the top eight seeds reached the quarter-finals of the Australian Open after overcoming Luxembourg’s Gilles Muller in Melbourne on Monday.

Djokovic cut a frustrated figure as he was made to work hard for a 6-4 7-5 7-5 win on Rod Laver Arena, the world number one’s mood perhaps not improved by knowing he faces more of the same big serving from Milos Raonic in the last eight.