The duo lost their opener against Canada on Saturday 2-1 to Canada, with Tomic toppled by Milos Raonic and Stosur shocked by Eugenie Bouchard – although they won the doubles.
Australia’s top-ranked male and female player now have to beat Italy and Poland to be any chance of winning group A and making Saturday’s final against the winner of group B.
Meanwhile, at the Brisbane International, the first big warm-up for the Australian Open, Ipswich’s Ashleigh Barty overcame Kiki Bertens in qualifying to set up a meeting with former world No 5 Daniela Hantuchova in round one on Monday.
Casey Dellacqua got a wildcard for the tournament but cops world No 2 Victoria Azarenka in the second round if she beats Kazak Gaina Voskoboeva.
In the men’s draw, Sydney 21-year-old James Duckworth has Jarkko Nieminen from Finland between him and Roger Federer in the second round, while Marinko Matosevic will reach Federer in the third if he get through his more favourable draw.
Although unseeded, Lleyton Hewitt will back himself in the second half of the draw with entirely beatable seeds in his way including Bulgaria’s Grigor Dimitrov, Japan’s Kei Nishikori and the best of them France’s Gilles Simon, who he wouldn’t meet until the semi.
See below for all the tennis coming up this “summer” (sigh, winter in London).
HOPMAN CUP DEC 28-JAN 4
BRISBANE INTERNATIONAL DEC 29-JAN 5
Mens: Roger Federer, Lleyton Hewitt, Gilles Simons
Womens: Victoria Azarenka, Daniela Hantuchova, Maria Sharapova, Heather Watson, Serena Williams
APIA INTERNATIONAL, SYDNEY JAN 5-JAN 11
Mens: Juan Martin Del Potro, Bernard Tomic, Radek Stepanek, Marin Cilic, Lukas Rosol
Womens: Agnieszka Radwanska, Petra Kvitova, Sara Errani, Jelena Jankovic, Caroline Wozniacki, Lucie Safarova, Daniela Hantuchova
Live on Eurosport in the UK and Channel 7 in Australia
Images via Getty