Knee injury forces Kyrgios out of Australian Open warm-up

The 21-year-old is receiving treatment on a left knee he reportedly damaged playing basketball, and will rest in the lead-up to the opening Grand Slam of the year starting on Monday in Melbourne.

Nick Kyrgios

Nick Kyrgios struggled during a 6-2, 6-2 defeat in less than an hour to American Jack Sock at last week's Hopman Cup.   -  Getty Images

Nick Kyrgios on Tuesday pulled out of a World Tennis Challenge exhibition in Adelaide with a knee injury in a setback to his Australian Open preparations.

"Unfortunately I am unable to play @WTCAdelaide this year. I have to rest & do all I can to be ready for #AO17 but I will be back next year," the Australian World No. 14 said on Twitter.

The 21-year-old is receiving treatment on a left knee he reportedly damaged playing basketball, and will rest in the lead-up to the opening Grand Slam of the year starting on Monday in Melbourne.

He struggled with the issue during a 6-2, 6-2 defeat in less than an hour to American Jack Sock at last week's Hopman Cup.

Kyrgios appeared less hampered on Monday night when he beat Rafael Nadal at an exhibition in Sydney under the Fast4 format.

Kyrgios's career has been marked by tantrums and even tanking, with Australia's highest ranked player only recently returning from a ban for a "lack of best efforts" during a controversial match in Shanghai last year.

France's Gasquet pulls out of Kooyong

Richard Gasquet withdrew from the Kooyong Classic Tuesday prior to his opening match, denying fans an all-French showdown with Gilles Simon.

The 12-man event is no stranger to late changes in the run-up to the Australian Open, the first Grand Slam of the year.

Organisers said Gasquet, who won the Hopman Cup last weekend with Kristina Mladenovic, was suffering with an abdominal muscle strain and would not be participating in the tournament.

Simon will instead face Croatian Ivo Karlovic.