The American tennis player John Isner's down and there may be a few more players yet to go out judging by the mounting injury toll just four days from the start of the Australian Open.
The 13th-ranked player has officially withdrawn from his Melbourne Park campaign due to a knee injury.
Question marks remain over a number of other seeded players at the Open.
Janko Tipsarevic, Kei Nishikori and Juan Monaco all pulled out of the Kooyong lead-up event in the space of 24 hours.
In Sydney, Jo Wilfried-Tsonga, Richard Gasquet and Gilles Simon withdrew before hitting a ball in anger while Radek Stepanek lasted just one match.
The world's top-two ranked women's players, defending Australian Open champion Victoria Azarenka and runner-up Maria Sharapova, also pulled out of the Brisbane event.
The run of injuries comes after former world number one Rafael Nadal scratched himself from the Open last month.
