"If people talk about me or not, I mean, to be honest, as long as I win, I'm happy," she said.
She had lost her previous three meetings against Williams.
"Serena has won so many Grand Slams and so many tournaments, something that I would love to achieve one day," Wozniacki said. "So to beat someone like her that I know that never gives up is definitely something that means a lot to me."
Williams, seeded 10th, was playing in her first tournament since January after being sidelined by a left ankle injury. She hasn't won a title since August.
There's still one Williams in the tournament: Venus plays No. 5 Agnieszka Radwanska in the quarterfinals Wednesday.