Tomic, pictured, was a 6-4, 6-4 winner over the world No.1 Djokovic, never really looking in trouble at any stage, and Serbia had to rely on Ana Ivanovic to beat Ashleigh Barty – she did so 6-2, 6-3 – to set up a doubles decider which the Serbs edged 6-4, 6-7 (8-10), 10-6 to secure their second win of the competition.
Francesca Schiavone and Andreas Seppi had earlier earned Italy a 2-1 win over Germany in the other Group A match. Italy had to come from behind to clinch the tie after Seppi lost his singles to Tommy Haas. Schiavone defeated Tatjana Malek, a late replacement for the injured Andrea Petkovic, before teaming up with Seppi to win the mixed doubles.
Seppi had been in a position to win both sets against Haas before losing 7-6 (7-3), 7-6 (9-7). Schiavone defeated Malek 3-6, 6-3, 6-3 and the doubles went 6-4, 7-5 in Italy's favour to secure their first of the event after their opening defeat by Serbia. The loss for Germany left them bottom of Pool A with no chance of making Saturday's final.
n Victoria Azarenka, the women's world No.1, began her build-up to the Australian Open with an imposing 6-3, 6-3 victory over big-serving Sabine Lisicki in the Brisbane International second round.
The Australian Open champion made light work of the German to set up a quarter-final against the qualifier, Ksenia Pervak. "I'm such a picky person that I probably will never be satisfied," she said. "It's a good thing because I have a lot more matches to play and I can always improve. But it was pretty good. I'm getting into the groove and I'm happy with where I'm at."
She faces a challenge to her top ranking from No.2 Maria Sharapova and No.3 Serena Williams when the Australian Open begins at Melbourne Park on January 14.
The leading men's seeds Andy Murray and Milos Raonic begin their campaigns against Australia's John Millman and the Bulgarian Grigor Dmitrov respectively.