MELBOURNE, Jan. 28 (Xinhua) -- World number four Novak Djokovic advanced to the Australian Open semifinals on Wednesday after fifth seed Lorenzo Musetti retired with a right groin injury despite leading by two sets.
Musetti was on course for the biggest win of his career after taking the opening sets 6-4, 6-3 against a below-par Djokovic. However, he suffered the injury early in the third set, struggled with his movement and retired while trailing 3-1.
Djokovic had taken a medical timeout after the second set, with his right foot strapped due to a blister.
"I feel really sorry for him. He was a far better player, I was on my way home," Djokovic said. "These things happen in sport. It's so unfortunate. He should have been a winner today."
Djokovic entered the quarterfinal after receiving a walkover in the fourth round when 16th seed Jakub Mensik withdrew with injury.
The 38-year-old will next face either two-time defending champion Jannik Sinner or eighth seed Ben Shelton. ■
