After four rounds of play, the eight quarterfinalists have been determined.  Not surprisingly, Novak Djokovic is one of them.  Before the first ball of the tournament was even struck, this Australian Open was thought of in terms of whether it would be won by Djokovic or the field, and the Serb has thus far done his part to keep the answer to that question a mystery.  He will next face the talented Kei Nishikori of Japan for the opportunity to move on to the semifinals.

On the surface, there is little reason to pick against Djokovic in this match.  He is firmly entrenched atop the men's rankings, and he has reached at least the finals of every tournament he has entered over the course of the last 12 months.  Furthermore, he has 10 major singles titles, half of which came right here in Melbourne.  In short, he does not lose often these days and rarely does so Down Under.

But nobody is going to dismiss Nishikori's chances of upsetting the top seed.  Fitness and injury issues have held him back, but he has really begun to consistently come into his own over the last 12 to 18 months.  He made his first major final two years ago in New York and once again qualified for the ATP World Tour Finals last season.  In addition to that, he now finds himself in his third Australian Open quarterfinal and has played better tennis than Djokovic to reach this point.

In particular, Nishikori's forehand has been in fine form.  It is a stroke that is typically more explosive and penetrating than the Serb's, and one that he is confident in using to dictate play.  It is also a higher-risk shot than it is for Djokovic, but he may well have to risk big to win big.  The seventh seed is quite speedy around the court as well, is consistent from the backhand wing, and has no qualms about moving forward to finish off points.  Most importantly, he is offensive-minded and is unlikely to make the mistake of falling too far back and allowing Djokovic to control the rallies.

The top seed is fully aware of the danger Nishikori poses, but he should also be confident that his game is superior.  His taller stature inherently gives him better angles and kick on his serve, and his forehand is more consistent.  Djokovic can inflict more damage off the backhand wing than the seventh seed, and his defensive skills are better in terms of both prolonging the point when necessary and finding a way to get back on offense.  In addition to that, he owns the best return in tennis, which means short of Nishikori having a fabulous day on serve, Djokovic should have a much easier time carving out break points and putting Nishikori under constant pressure.

Of course, possessing the better game means nothing if one is unable to execute.  After logging one of the worst performances of his career against Gilles Simon in the round of 16, Djokovic needs to come out and deliver.  For his own part, he did not admit to nerves but instead cited a bad day at the office.  He said he would take confidence that he had still secured victory in spite of all of his unforced errors, but there is no question that he needs to raise his level if he wants to avoid any doubts creeping in to affect his game or to give the rest of the field too much hope.  Nishikori is not apt to let him get away with such poor play either.  He is getting more at ease in playing these kinds of matches, and he was the man who punished Djokovic for his lackadaisical play in the semifinals of the US Open two years ago.  With the kind of tennis he has been producing this tournament, he should have no trouble believing he could get the better of Djokovic here under similar circumstances.

In the end, this match is mostly on Djokovic's racquet, but there is the feel of a possible upset in the air.  At some point, even the best come back down to the earth, and maybe Nishikori is the man to derail Djokovic's run this year in Melbourne.  One should still expect to see Djokovic advance, but without him raising his level of play, it is nowhere near a guarantee.    

128 women arrived in Melbourne in search of a Grand Slam singles title, and now only eight remain.  Among them are two of the usual suspects who always seem to be in the hunt for a major title, Serena Williams and Maria Sharapova.  They have managed to avoid the upset bug that has struck down so much of their opposition to set up the marquee quarterfinal people have been talking about ever since the draw was originally made.

It is easy to understand why this quarterfinal is thought of as “must-see” tennis.  Williams and Sharapova are two of the top names in the sport.  Williams has been the most dominant player in women’s tennis over the last few years.  She has won an impressive 69 titles, including a staggering 21 major singles titles.  Sharapova is a former No. 1, who has won five Grand Slam singles titles and 35 tournaments overall.  Given these statistics, it is only natural that most would classify an encounter between the pair as a clash of the titans.

Yet, despite their respective accomplishments and places within the game, it could be argued that it is somewhat puzzling that a meeting between these two is billed as tennis that is not to be missed.  They have met 20 times, and Sharapova has only won on two of those occasions – both coming more than a decade ago.  The reason for the lopsided rivalry is that this is simply a bad matchup for Sharapova.  A key component of the Russian's success stems from her ability to out slug her opponents from the baseline by utilizing her superior firepower and consistency.  Unfortunately for her, that is the way Williams has secured so much of her own success, and she does it better than Sharapova.  She hits bigger and is quicker around the court, and then there is the matter of their serves.  The American owns the greatest serve – first and second – in the history of the women's game.  By contrast, Sharapova's serve can be a liability, producing aces and double faults in equal measure.  The fifth seed is going to need to have an excellent serving day and find a way to employ the drop shot and volleying skills she has added to her arsenal if she is to secure her third victory over Williams.

The other element Sharapova needs going into this match is the belief that she can beat Williams.  In this area, Sharapova does herself proud, and it is probably the reason why her matches against Williams continue to receive so much hype in spite of her dismal head-to-head against the top seed.  Sharapova is a fierce competitor who has repeatedly shown her willingness to fight and find a way to win even when not at her best.  She may take to the court knowing the odds are stacked against her, but no one doubts her desire to fight and try to find some way of overcoming the challenge that is Williams. 

Of course, Williams' mental approach to this match has to be factored in as well.  Williams knows what she is going to get from Sharapova and is comfortable handling it. Based on her record, she also knows that she can dominate the Russian.  And whether it is because a part of her still wants to make Sharapova pay for that 2004 Wimbledon final defeat or simply because she knows she needs to bring her best against a player of Sharapova's caliber, Williams always seems to show more purpose and determination when she takes on the Russian.  When she comes out of the gates so focused, it is hard for Sharapova to gain an early foothold and plant seeds of doubt in American's mind that this time around will be different than any other meeting in the last 10 years.

Suffice it to say that most signs point towards a Williams victory.  The possibility is there for Sharapova to turn the tables on the top seed.  She has the belief and definitely the weapons to potentially trouble Williams and take advantage if the American is off her game.  But either Sharapova is going to have to play the match of her life or get help from Williams if she is to cause an upset, and neither scenario looks likely at the moment.  Look for Williams to advance to the final four.