Stefanos Tsitsipas has advanced to the Australian Open quarter-finals after Matteo Berrettini withdrew prior to their match on Monday night due to an abdominal strain.

Ninth seed Berrettini suffered the injury in the third set of his 7-6(1), 7-6(5), 7-6(5) third-round victory over Karen Khachanov on Saturday. He received a medical time out during the match to relieve pain in his abdomen.

“I’m really sorry to say that I got injured in the last match that I played,” Berrettini told reporters on Monday. “I felt something on my ab. I thought that [it] wasn’t something really big, but the next day when I woke up I felt it was big. So I spoke to the doctors and they told me, ‘Look, it can get [much] worse’. So it’s not worth trying. I’m not 100 per cent. To beat these guys, you have to be 100 per cent. I think it’s not really professional to step [onto court] when you’re not the best.”

Berrettini, who has an 8-2 record on the 2021 season, led Italy to the recent ATP Cup final (l. to Russia). The 24-year-old had been attempting to become the fourth Italian man to reach the Australian Open quarter-finals, after Giorgio De Stefani (1935), Nicola Pietrangeli (1957) and Cristiano Caratti (1991).

“I was really feeling well… The ATP Cup was great. The first three rounds I was playing really good, so [I] enjoyed [the] atmosphere… It’s just bad luck.”

Fifth seed Tsitsipas will now prepare to face 2009 champion and second seed Rafael Nadal on Wednesday in a bid to reach his second Australian Open semi-final (2019). Nadal leads Tsitsipas 6-1 in their ATP Head2Head series.