Second-seed Azarenka beat Italy's Flavia Pennetta 6-4 6-2 and will now face an opponent she has beaten just three times in 15 meetings.
Two of those wins have come this year, on hard courts in Doha and Cincinnati, but Azarenka isn't reading too much into those results.
"It's not that I don't care what happened in the past, but I don't think there is a need to pay so much attention to what happened," said the Belarusian. "It's always a new story.
"I don't even think that it's going to be close to the same as it was last year.
"We know each other pretty well. I know her strengths; she knows my strengths."
Last year's final went to three sets with Williams edging the final set 7-5 but Azarenka believes her game has improved in the past 12 months.
"It hasn't changed tremendously but there are aspects that got better physically," said Azarenka, who will be trying to add the US Open crown to her two Australian Open grand slam titles. "Mentally I felt like (this year) was a great turning point for me on some level for my career.
"I feel like I'm a better player. I'm a more complete player."
Azarenka didn't sparkle against Pennetta, grinding out a win in a match which saw her serve broken five times and she conceded that she struggled to find momentum.
"There are always things that can be better. I felt like the first set was a little bit tricky - the momentum wasn't there," she said.
"Just being able to pick up and raise the level in the important moments, that's what it's all about, to be able to do that."
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- Flavia Pennetta