Sharapova has barely been pushed in her successive 6-0 6-0 victories over Olga Puchkova and Misaki Doi at Melbourne Park and while Williams has slipped down the rankings due to injuries and a fatigue-inducing illness, the Russian is not expecting anything other than a taut battle on Rod Laver Arena.
"There are certainly no secrets coming into that matchup. We've played against each other many times," Sharapova said of the clash against the seven-times grand slam champion.
"Despite the fact that she might not be seeded high or didn't play for a little bit, she's still a very experienced player and a tremendous athlete.
"You certainly know what she's capable of. But when you're out on the court, you're not thinking how many titles she's won or how experienced she is.
"You're thinking about what you need to do to step it up in a certain situation and win as many points as you can."
Men's champion Novak Djokovic, who has been almost as ruthlessly efficient as Sharapova in his first two matches in his quest for his third successive titles, will play Radek Stepanek of the Czech Republic for a place in the fourth round.
Djokovic destroyed up and coming American Ryan Harrison in the second round on Wednesday, making the game look ridiculously easy, and in kind of form should extend his lifetime record against Stepanek to 8-1.
Their last meeting ended in a four-set victory in the third round at Wimbledon last year.
While the Williams-Sharapova clash is expected to highlight the day on Rod Laver, the first game on the centre court could provide a glimpse into the future with 17-year-old American Madison Keys facing fifth-seed Angelique Kerber.
Keys has been lauded by commentators for not only her game but also her maturity beyond her age. She is also considered one of the best young players on tour by her fellow professionals.
Women's number four Agnieszka Radwanska, who is unbeaten this year after winning the Auckland and Sydney tournaments, will seek to extend that streak to 12 matches when she plays Britain's Heather Watson on Hisense Arena.
Radwanska beat Watson 6-0 6-2 in the Wimbledon third round last year, but the British 20-year-old feels like she has improved her own game markedly since then.
"I think the first time I played her I just went guns blazing, didn't know what to do," Watson said.
"Just went for way too much. This time I'm coming in a different player, and I'm going to approach it differently."
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