Tim Cahill has emerged as a major injury doubt for Australia ahead of their World Cup opener with Germany in Durban on Sunday.
The Everton midfielder continues to be troubled by the neck injury he suffered during the 3-1 warm-up defeat to the USA on Saturday.
Cahill was restricted to solo shooting practice at the side of the pitch as the rest of Pim Verbeek's squad - including Harry Kewell - took part in an intense two-hour training session.
Kewell looks to be winning his battle against the much-discussed groin injury which has dominated Australia's build-up, but the possible absence of key man Cahill will be a serious concern.
With 20 goals from 40 appearances, Cahill has scored more than any other member of the Australia squad.
He famously netted the first World Cup finals goal for Australia four years ago when his two late strikes against Japan secured the memorable come-from-behind 3-1 victory in the opening game in Germany.
But while there is now some doubt over Cahill for the opening game in Durban on Sunday, Kewell seems to have won his fitness battle just as Verbeek predicted all along.
The 31-year-old, whose late goal against Croatia four years ago secured Australia's passage to the knockout stages of the World Cup for the first time, trained strongly and looks set to be ready to face Germany.
Kewell missed both of Australia's warm-up games against Denmark and the United States but appears to have timed his return to fitness to perfection.
Australia's other big injury concern for their third World Cup finals appearance following 1974 and 2006 in midfielder Brett Emerton also joined in full training and looks to have overcome his recent calf problem.