With Andy Murray still searching to find his best form, the Big 4 has presently been reduced to the Big 3.  Yet although their number has temporarily been reduced by one, many are still wondering if anyone outside the elite group consisting of Roger Federer, Rafael Nadal, and Novak Djokovic will be the last man standing when the year's final major draws to a close.

There is certainly ample reason to doubt it will be anyone outside of these three men.  They have proven to be very stingy when it comes to the slams, with all three of them having won multiple titles here in New York as part of their overall major totals.  Recently for his own part, Federer has proven himself a force to be reckoned with for the better part of the last eighteen months with his performances at the majors and Masters events. And given that he managed to make the final in Cincinnati despite being rusty in his first tournament since Wimbledon, he is sure to be that much more of a threat when he is sharper in New York. 

Like Federer, Nadal has been a tough out the last year-and-a-half, and that includes his play on the summer hard courts.  He is apt to be feeling confident about his game after securing the title in Toronto a few weeks ago, and with the way he mowed through the field to take the title here last summer, he can be plenty optimistic that he is in prime position to repeat that feat.

And then there is Djokovic, the man who came late to the party as far as favorites go, but with his exploits this summer has shot himself to the top of many fans' lists as a tournament favorite.  He was still struggling to find his form this past spring but found something special to reign victorious at Wimbledon, giving him a much-needed boost in confidence.  He has since followed that up with a victory in Cincinnati, becoming the first to hold all nine of the Masters titles.  If he can keep that momentum going, another US Open trophy could be in the cards.

Suffice it to say, all three of these competitors still represent a daunting challenge to the rest of the field's title hopes, but there are a couple of areas where the opposition might find some hope.  For starters, typically the best time to try and upset one of these champions is early in the tournament.  They are not quite as locked into their best, and the match itself does not come with as much mental pressure given that it is not quite as significant as the later rounds, which aids the less-accomplished and less-experienced players when they take on these giants of the game.  Both Nadal and Federer, in particular, do face some potentially tricky hurdles, with Nadal slated to meet Karen Khachanov and Federer to face Nick Kyrgios in the third round.  Some wily veterans in the early rounds could also pose a challenge if the Big 3 are not ready to go straight out of the gates.

In addition to some potential early tests, fate proved unkind to Federer and Djokovic in that they were placed in the same quarter.  As such, that means only two members of the Big 3 can make it through to the semifinals, leaving two berths open for the remaining members of the field.  Interestingly enough, the two quarters vacant of any members of the Big 3 feature Marin Cilic, Juan Martin del Potro, and Stan Wawrinka, the other three men in the field to have won this title.  Cilic and del Potro, in particular, are seen as outside favorites to possibly upset the apple cart and walk away with the title.  If they can live up to their own respective seeding, then it will undoubtedly provide some food for thought at the business end of the event.

As always, only time will tell how the final major of 2018 will unfold.  There are definitely players in the field who are capable of defeating the tournament favorites to be the one left hoisting the trophy, and depending on what transpires in the first week, their odds may only increase.  That said, Federer, Nadal, and Djokovic are favorites for a reason, and as has been the case for over a decade now, it would be a stunner if anyone other than one of these three men leaves New York as the 2018 US Open Champion.