Williams, the world No. 1, defeated third-seeded Maria Sharapova 6-2, 7-6 (9-7) in the semifinals Friday despite landing just 40 percent of her first serves and dropping serve four times.
Williams had seven aces but also seven double faults. Sharapova had eight double faults herself.
Neither player was very successful serving. Williams, who had been very sharp in her first two matches at Brisbane, took 53 percent of the points off Sharapova's serve and piled up six breaks. But she only won 51 percent of the points when serving.
Azarenka, whom Williams replaced atop the WTA rankings last year, rallied for a 1-6, 6-3, 6-4 win over No. 4-seeded Jelena Jankovic. Again serving was an issue as Azarenka and Jankovic also combined for 15 double faults.
Both players had six breaks but half of those against Azarenka came in the first set. She allowed only one break in the final set, while getting two herself.
Williams owns a 13-3 series edge over Azarenka, They played four times last year -- all in tournament finals -- with Williams winning three times, including a three-set win at the U.S. Open.