Novak Djokovic has barely blinked an eye at the Australian Open.
The tournament's No. 1 seed was flawless through the first three rounds, going a perfect 9-of-9 in taking down Paul-Henri Mathieu, Ryan Harrison and Radek Stepanek.
After enduring a grueling five-set win against Stanislas Wawrinka Sunday, the world's No. 1 is one step closer to capturing his fourth Australian Open win. However, while Djokovic didn't face stiff competition early on, several stars stand in his way.
Let's take a look at the top threats to taking down the Australian Open's No. 1 seed.
Roger Federer (No. 2 seed)
No player represents a bigger threat to Djokovic's title chances than the second-best player in the world, Roger Federer.
The tennis legend has enjoyed tremendous success in this tournament, capturing four titles in his illustrious career. It was only two years ago that Federer emerged victorious at the Australian Open, toppling Andy Murray.
In both 2011 and 2012, Federer reached the semifinals but couldn't advance.
Through three rounds the Swiss star looked cool, calm and relaxed in the Australian heat. While Djokovic has already secured a spot in the quarterfinals, Federer must take down No. 13 seed Milos Raonic to move on. While Federer wouldn't face Djokovic until the final, the 15-year pro has the skill and experience to spoil Djokovic's title hopes.
Andy Murray (No. 3 seed)
In just eight years as a pro, Scottish-born Andy Murray has won 383 matches, including the 2012 U.S. Open.
A two-time Australian Open runner-up, Murray will be looking to get over the hump as the tournament progresses. Through three rounds, he's been typically efficient, winning each matchup in straight sets.
The fiercely competitive 25-year-old is the third-ranked player in the world, so he'll have plenty of motivation if he eventually faces Djokovic in the final. Like Federer, Murray must still seal his spot in the quarterfinals and will face No. 14 seed Gilles Simon of France.
Murray's versatility and consistency make him a constant threat and a legitimate threat to taking down the tournament's top seed.
Tomas Berdych (No. 5 seed)
The first big test for Djokovic will come sooner than later as he takes on No. 5 seed Tomas Berdych in the quarterfinals. The 27-year-old out of the Czech Republic is the No. 6 player in the world for good reason.
Since turning pro in 2002, Berdych has advanced to the quarterfinals twice at the Aussie Open, was the runner-up at Wimbledon in 2010 and reached the semifinals in the U.S. Open last year.
Like his chief competitors, Berdych's road to the quarterfinals has been a fairly easy one. He skated through the first three rounds on straight sets before battling 31st-ranked Kevin Anderson on Sunday. Berdych ultimately prevailed, setting up a quarterfinal showdown with Djokovic.
Djokovic should be the prevailing favorite, especially considering Berdych's history against top competition, but this could be Berdych's chance to prove himself on the big stage.