Carlos Alcaraz stayed on course for a blockbuster Australian Open quarter-final with Novak Djokovic when marathon man Jack Draper retired during their last-16 clash on Sunday. The Spanish third seed was well on top when the Briton threw in the towel when down 7-5, 6-1 on a sweltering Rod Laver Arena. The 15th-seeded Draper needed five sets to win his first three Melbourne matches, rallying from behind in all of them to stay in the tournament. He had spent nearly 13 hours on court to Alcaraz's six and it finally caught up with him.