After nearly two weeks of exciting tennis, the men's draw has been whittled down to four players.  Not surprisingly, one of those four is Novak Djokovic.  But it has hardly been smooth sailing for the Serb to get to this point, and he should be prepared to potentially hit a few more bumps in the road when he takes on Marin Cilic in his attempt to make four successive Grand Slam finals.

On the surface, the numbers would suggest that Djokovic is a heavy favorite.  He has nine major singles titles to just one for Cilic.  He is currently ranked No. 1 and has been established in the upper echelon's of the men's game far longer than Cilic.  Djokovic has also played Cilic 13 times and has yet to lose a match to the Croat.  But no matter how wide the gap in their accomplishments or one-sided the past history is between a pair of players, there is no reason why the ninth seed cannot trouble Djokovic. 

Cilic is equipped to earn his fair share of cheap point on the serve, although against the best returner in the game, he is going to have to maintain a high first-serve percentage.  He also does a better job of moving forward and looks to be more comfortable up at the net than the Serb.  If he is able to get up there with any kind of regularity, that kind of constant pressure could extract errors from Djokovic.  And while Cilic does not do it quite as well as the top seed, his movement is exceptional for a man of his size and allows him to shrink the court with his ability to get a racquet on the ball and keep it in play.

For all that Cilic has the requisite weapons to trouble Djokovic, however, the current No. 1 is clearly the superior player.  Assuming his return is clicking, he should get more looks at breaking Cilic's serve than Cilic will his, especially if he is having a good serving day himself.  Furthermore, he is better at covering the court and hitting more effectively on the run, and the consistency he is able to produce from the back of the court is sure to test Cilic, who can be goaded into going for too much under pressure.  

But the conundrum of dealing with pressure is not just reserved for the lower-ranked players.  Djokovic will not be immune to the moment either.  He has not been playing poorly, but after coming up short  in Montréal and Cincinnati, and dropping sets in his last couple of matches here, he is hardly happy with his game.  He is clearly feeling the weight of expectations that come with trying to make four finals in a row, and as a result, he has looked edgy and at times sloppy prior to this stage of the tournament.  He can ill afford to perform that way against Cilic, who despite having yet to garner a victory over Djokovic will not be lacking in belief.  They have met four times at a major, and with the exception of when they met at Wimbledon a few months ago, all have been competitive encounters.  Cilic appears to be a man who has risen to the occasion in his attempt to defend his US Open title, and when a player is able to draw inspiration from a venue that has been the site of his greatest triumph, there is no telling what he will be able to accomplish.

So could Cilic cause yet another upset at this year's US Open?  The answer is yes.  Few would have pegged him to get his first win over Federer in the semifinals here last year before going on to win his first major, but he did it anyway.  That considered, however, Djokovic has to be the pick to get through to the final.  He has had such a dominant season, and as he has proven time and again, he is excellent at finding a way to cross the finish line even when not playing his best.  He might very well be tested, but expect Djokovic to book a place in the championship match on Sunday.

It is never easy to contest a major singles semifinal.  It is never easy to face a countryman.  On Friday, Roger Federer and Stanislas Wawrinka will find themselves in the unfortunate position of having to overcome both of those challenges as they square off in a match where the only guarantee is that a man from Switzerland will advance to vie for the 2015 US Open title.

As with the other men's semifinal, on paper there is a clear heavy favorite, and it is Roger Federer.  He is the most decorated player in the history of the men's game with 17 major singles titles.  He has accumulated a greater number of overall titles than Wawrinka, and he has vastly more experience managing the pressure and expectations that come with contesting matches of this magnitude than his compatriot, whose most noteworthy success has only come in the last couple of seasons.  If all of that were not enough to have Federer looking like a lock, his dominant 16-3 record against Wawrinka would.  

But Federer will undoubtedly be aware Wawrinka is a dangerous opponent who could make life difficult for him.  Like Federer, the lower-ranked Swiss has a balanced, all-around game.  They are both not shy about going on the offensive and know their way around the forecourt.  Federer's backhand is the more versatile of the pair, and the top-ranked Swiss possesses superior foot speed as well.  He does a better job extending the points when he has to call on his defense and is generally the more consistent of the two.  Federer does not hold all of the cards, however.  It is Wawrinka who boasts greater firepower from the ground, and if his game is firing on all cylinders, he could have Federer on his heels much more than the second seed would like.  

For evidence of Wawrinka's ability to boss Federer around the court, one need look no further than their most recent meeting, when Wawrinka blitzed Federer in straight sets at Roland Garros this past spring.  The fifth seed was able to make more headway in the points on that occasion because his groundstrokes had more sting and penetrated through the court more quickly.  It is that kind of performance that should give Wawrinka the confidence he needs on Friday in spite of his dismal record against his countryman.  The fact that Wawrinka also has two major singles titles to his name and had to defeat some hefty opposition en route to them should help his cause too.  

Of course, Federer has ample cause to feel optimistic about his own chances of advancing to the final.  As mentioned earlier, this is far more familiar territory for him than it is for Wawrinka.  He came into this tournament on the back of winning the title in Cincinnati, and he has been producing the highest level of tennis of any of the four semifinalists.  And while Wawrinka did get the better of him at Roland Garros, Federer will remember that that loss, along with his other two to Wawrinka, have all come on red clay.  The Swiss No. 2 has yet to defeat Federer on the faster surfaces, and Federer will be confident of keeping that streak intact.

It is hard to bet against Federer keeping that particular streak unblemished.  Like Cilic against Djokovic, the lower-ranked Wawrinka has the talent and the game to garner an upset, but also as with Cilic and Djokovic, it is difficult to envision the clear favorite failing to advance.  Federer is playing too well right now, and it is going to take something extra special from Wawrinka to knock Federer off course and deny him another look at capturing an 18th major singles title.