Williams will face off against second seed Victoria Azarenka of Belarus on Sunday. Last year, Azarenka nearly beat Williams in the final, until the tennis star moved ahead to 7-5 in the third set.
"I know her game as well as she knows mine," Williams said. "She knows what I do great, what I do bad, and what I can do better. I know the same thing. At this point, it's just all about just playing some tennis now."
Williams, who hasn't lost a set this year in singles, will be trying for her 17thGrand Slam title and fifth U.S. Open championship. She previously won the U.S. Open without dropping a set in both 2008 and 2002.
Are you rooting for Serena or Victoria?