Nick Kyrgios finally arrived at Kooyong Lawn Tennis Club on Wednesday afternoon and had his first hit on the grasscourts, bidding to prove his fitness ahead of Australia’s Davis Cup tie against the United States.

Kyrgios has been battling a mystery virus picked up in Dubai last week, with his late arrival in Melbourne sparking conjecture that retired team captain Lleyton Hewitt could make a shock comeback.

Sam Groth – who will partner John Peers in Saturday’s doubles rubber – also says he is ready to step in should Kyrgios (back/hip/virus) or Bernard Tomic (wrist) be forced to pull out of Friday’s opening singles matches.