In Sunday's final, the 20-year-old Dane will face Julia Goerges, the first German woman to make the Stuttgart trophy match in 15 years.
"Agnieszka is a good player, she's very sneaky and knows how to run her opponent around," admitted Wozniacki, who took 65 minutes to clinch the first set against the 14th-ranked Pole.
Wozniacki said she is looking forward to playing crowd-favourite Goerges.
"I have played Julia before," said the Dane. "I know she's a good player and has been hitting some good shots.
"It will help her to have the crowd behind her, but I am looking forward to the final."
Goerges, 22, became the first German for 15 years to reach the final here when she beat Australian fifth seed Stosur 6-4, 3-6, 7-5.
"It is unbelievable to have beaten a player like Stosur and in front of a home crowd. I'm just too happy for words, " said Goerges, ranked 32nd in the world.
"It was one of my best matches ever, I played right to my limits."
This is only the third time Goerges has reached a WTA final and she is the first German to reach the Stuttgart final since Anke Huber, who was the runner-up to Martina Hingis in 1996.
"I have nothing to lose now in the final," she said. "Having the crowd behind me will, of course, be a big plus."
Stosur, who reached the French Open final last year after losing to Justine Henin in the 2010 Stuttgart final, said she was disappointed, but happy to have reached the last four this year.
"I definitely felt like I was back in the match. When it came down to it, she was probably a bit more aggressive than me," said the 27-year-old.
"At crucial times she managed to get herself ahead. I am obviously disappointed to have lost the match, but it is encouraging to have come here and played well.
"I probably haven't played with this much confidence all year, I have come through and played four good matches here.
"It is disappointing to lose, but it is definitely something I can build on."
Goerges and Wozniacki are playing for the winners prize of a brand-new sports car worth 111,000 US dollars, which could present her with a problem.
"I haven't driven a car for three months now, maybe if I win, I should try to drive again with a normal car first," she joked.