Teenage ace Nick Kyrgios has declared himself fit to begin his Australian summer tennis campaign after overcoming a back complaint.

The 19-year-old Wimbledon quarter-finalist withdrew from this week’s Hopman Cup in Perth because of the injury, but he indicated on Thursday he will be ready to play in the Sydney International starting on Sunday.

All going well, Kyrgios will also take his place at the Australian Open in Melbourne from January 19.

The new Australian No.1 enjoyed a 45-minute workout on Thursday at Olympic Park, the venue for the Sydney International.

“Good hit out on #RosewallArena @SydneyTennis,” he tweeted.

“Felt good and looking forward to cracking on with the Aussie Summer.”