Nobody can argue that Kei Nishikori is playing the best tennis of his life. Just two spots off his career high ranking of 9 (which he obtained less than three months ago), Nishikori has had some stellar results in 2014. But more importantly he’s put together a string of stellar performances at this US Open. After skipping most of the summer hardcourt series with a toe injury, there was some doubt if Nishikori would even play at Flushing Meadows, let alone do well. And then there was his draw. Facing a round of 16 matchup with the #5 seed Milos Roanic, followed by #3 Wawrinka, Nishikori had arguably the most challenging draw of all the second tier players in the tournament (ie everyone not named Djokovic or Federer).

Nishikori rose to both of those challenges with aplomb. First he fought off 35 aces from Raonic, coming back from two sets to one down to clinch a five set victory. This win alone was impressive, given Raonic too had finally come into his own and has been in the form of his life. What came next was even more remarkable as he outlasted Stanislas Wawrinka in five to make his first Slam semi-final. This, of course, brings him face-to-face with Novak Djokovic. The two have played only twice before, and both of those matches were well in the past. Djokovic beat a 20 year old Nishikori at the French Open on clay in 2010, only to lose to him on hard courts the following year. Of course even if Nishikori wasn’t coming off back-to-back five set matches, Djokovic would still be the firm favorite for this match on paper. His tennis resume far outstrips Nishikori’s and he is the #1 ranked player in the world. But here’s three reasons why Nishikori might pull the upset today.

1) Nishikori Possesses A Great Return

For a 6’3 elite player Djokovic’s serve is decidedly sub-par. It isn’t a bad serve, per se but neither is it a particularly good one. Nishikori possesses a skilled enough return to actually hurt Djokovic off the return in a way that, say Federer, typically does not (because Djokovic can largely serve to the Federer backhand). Nishikori will be able to start many of the points on Djokovic’s service games either ahead or on neutral terms – which is critical for him if he is to stand a chance today. Especially given the inevitable miles on his legs from the past two matches, Nishikori can’t afford to spend extended periods of this match playing on defense.

The second element that plays into this is that Djokovic gets tight on his serve sometimes, and has been known to throw in some critical double faults at critical junctures. If Nishikori can consistently bring some pressure onto Djokovic’s serve that might pay dividends and prove a turning point in the match.

2) Nishikori Can Be Patiently Offensive

While Djokovic lacks the firepower of some of the bigger hitters he is capable of respectable offense. However it is his amazing defensive ability that has netted him so much success. One thing that separates out the great players is their ability to win matches even when they aren’t playing their best. Against all but the very best, Djokovic can simply default into “grind mode” where he scrambles, makes a ton of balls and just waits for his opponent to make mistakes. Against players like Berdych, Tsonga and the like this is largely successful because those players lack the patience and point construction to attack Djokovic in a truly sustainable manner. This is one of the reasons why Wawrinka has matched up so well with Djokovic traditionally (even though he’s failed to win most of them) – Wawrinka comes at Djokovic with, what is for him, sustainable firepower.

While Nishikori obviously doesn’t have Wawrinka’s heavy hitting he is naturally a slightly more offensive player than Djokovic. Although he lacks a true killer punch Nishikori has a very balanced game and can maintain aggressive play off both wings. Being a smaller player, he’s learned how to construct points with some level of patience, and is just as happy to put Djokovic in a position to make an error as he is hitting a winner. If he can sustain that patience and find the appropriate level of aggression Nishikori can put himself in control of this match and take advantage of Djokovic’s defensive tendencies.

3) Nishikori Has A More Complete Game

It’s true. Nishikori has a very complete game. But what is of particular relevance here is the slice backhand and volleys. While I don’t expect there to be a lot of slices backhands hit in this match, the volleying angle could prove critical. Nishikori is very competent around the net, which is the one area of Djokovic’s game that is sorely lacking. Both players possess great speed and defensive skills. Both players will be forced to come forward and finish at the net to put some points away. In this regard, Nishikori has an edge on Djokovic that just might prove critical.

Will it make the difference? Only if Nishikori is able to take advantage of the first two points – good returning and patient offense.

Conclusion

This is still Djokovic’s match to win. Given the quality of Nishikori’s tennis lately if he had been fresh I would consider this to be a true toss-up purely because of the matchup. However since neither player possesses a true knockout punch, this match will be marked by long rallies, cagey play and lots of running. Given the fatigue Nishikori must surely be feeling the odds are against him. However if he does manage to play well enough and more importantly intelligently enough, he just might be able to edge Djokovic out.