Serena Williams has expressed her excitement ahead of this weekend's Australian Open final.

The 33-year-old will take on Maria Sharapova for first Grand Slam title of the year, after beating fellow American Madison Keys on Thursday.

"I'm really excited to be in the final again, I didn't come here with that expectation," Williams told reporters.

"I'm happy to be in this position. I have to win against Maria. She's unbelievable. I'm glad that it's number one against number two in the final."

Williams has won five Australian Open titles in her career, with her last victory coming in 2010.