The No. 3 seed has dropped fewer than 10 matches for the entire tournament and recently booked her spot in the final eight with a crushing 6-2, 6-0 victory over 14th seed Maria Kirilenko.
Incredibly, the win was her 20th consecutive Grand Slam victory, having won the U.S. Open and Wimbledon last year.
Williams is without a doubt the clear favorite to take home the opening Grand Slam crown of the year and move up the world rankings once more in the process.
But there are several large threats remaining in the competition who could well challenge Williams for the 2013 Australian Open title. Read on to see who the biggest threats remaining at Melbourne are for the 31-year-old.
The biggest threat to Williams is probably the World No. 1, Victoria Azarenka, whom Williams could be set to meet in the semifinals.
The Belarussian pushed Williams all the way in a tight three-set match when they clashed at the final of the 2012 U.S. Open, and having won just last year in Melbourne, Azarenka will no doubt be confident that she can improve on that result in 2013.
Azarenka recently breezed through to the final eight of the tournament with a 6-1, 6-1 thrashing of in-form Russian Elena Vesina—taking less than an hour to do so and winning a staggering 68 percent off her opponents' serve as well.
She'll play Russian legend and former Grand Slam champion Svetlana Kuznetsova in the quarterfinals for a chance to take down Serena Williams in Melbourne.
One of the few women ever to beat Williams in a Grand Slam final is Maria Sharapova, having won the 2004 Wimbledon crown in straight sets.
And while she won't get a shot to play the 31-year-old until the final again this year, expect Sharapova to certainly give the American a run for her money again this time around, with her powerful ground strokes capable of wreaking great havoc here.
Sharapova's ability to hit winners and find the lines is a great attribute that will help her against Williams—another great hitter of the modern game. If the World No. 2 can get her driving forehand going against Williams, expect this one to be another close match.
Sharapova is one of the few women who can match Williams in terms of power and hitting ability, so we could be in for one fantastic Grand Slam final.
Polish star Agneiszka Radwanaska might be flying under the radar a little bit at the 2013 Australian Open, but having reached the final eight once more, perhaps the spotlight will once again start to shine on the No. 4 seed.
Radwanska recently won convincingly over Ana Ivanovic in her fourth-round match and will play former Grand Slam champion Li Na in the quarterfinals.
If she wins, she'll likely play Maria Sharapova in the semifinals for a shot to take on Williams in the final and make up for her Wimbledon heartbreak. The Polish star pushed Williams all the way in a tight three-set match, but having won the second set, she succumbed to the American 6-2 in the third set.
She'll be looking to improve on that here, and will no doubt have the confidence that she can take points, sets and eventually the match off the American.
Radwanska is in great form so far this year, and that form could well lead to her maiden Grand Slam title at the 2013 Australian Open over Serena Williams.
Who do you think the are biggest threats remaining for Serena Williams?
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