America's Serena Williams and Mardy Fish overpowered Alicia Molik and Peter Luczak to demolish Australia's outside chance of a Hopman Cup final.

The beating left Molik in no doubt Williams could defend her title at the Australian Open, which begins on January 14.

"She could win the Australian Open without a doubt, she is executing her shots pretty well ... I feel she has a bit more pace up her sleeve," Molik said.

Williams defeated Molik 6-2 7-6 (9-7) in the opening women's singles rubber before Fish edged out Luczak 7-6 (7-2) 7-6 (12-10).

The US pair then completed the 3-0 rout with a 6-2 6-3 mixed doubles victory.

The Americans progress to Friday's final, where they will meet the winner of group A - to be decided after ties between top seeds Serbia and Argentina and France and Taiwan.

Neither Australian gave their opponents an easy run but were better at fending off match points than taking them.

Molik recovered from a poor start to hold on grimly in the second set against the increasingly-frustrated World No.7 before double-faulting on match point.

Luczak pushed Fish to the limit, prompting the American to sing his opponents' praises after the match.

"I look forward to seeing his ranking rise in the next few months," Fish said.

Luczak believed he and Molik were in with a chance in his first Hopman Cup.

"You don't go out there to get smoked," he said.

Williams said she was approaching the form required to defend her title at the Australian Open beginning on January 14 in Melbourne, and will spend the next two weeks relaxing.

Meanwhile, Molik was feeling confident despite her loss to Williams.

"She hit me with a barrage of shots in that first set ... it took me a little while to get used to that and I started dictate a bit of the play," she said.

"I was certainly pushing her game for game."

If Serbia win they are guaranteed a place but a loss could allow either France or Taiwan a chance.

Friday night's $1 million final will be the second for Williams, who won in 2003 with compatriot James Blake.

The host nation has only won the Hopman Cup once, when Mark Philippoussis and Jelena Dokic grabbed the title in 1999.

Brought to you by AAP © 2024 AAP