‘Leyton is suffering from a viral infection and a high temperature,’ Australia’s coach John Fitzgerald told reporters.

‘He simply can’t get out of bed. As one door closes another opens and this is the opportunity of Chris Guccione’s life,’ Fitzgerald said after naming Australia’s third-ranked singles player to face world number three Djokovic.

Serbia leads the world group playoff tie 2-1 after winning Sunday’s doubles and need one more point to reach the top division for the first time as an independent nation.

Janko Tipsarevic faces Australia’s Paul Luzak in Sunday’s second singles rubber.