Rafael Nadal, Roger Federer or Andy Murray will be dueling for more than just US Open glory when the trio arrive in New York for the final Grand Slam of 2017. All three could feasibly end the fortnight at Flushing Meadows as world number one, a position currently occupied by Nadal following Federer and Murray's recent injury withdrawals.
The Spaniard, who has won four titles in the calendar year so far including a 10th French Open title, is now in pole position to win the US Open and end the year on a high.
However, he will come under pressure from two of his main rivals from the last decade of his career. Federer, who pulled out of the Cincinnati Masters due to a back problem, is close on his tail and is bidding to regaining the world number one ranking for the first time since October 2012.
Murray has not played due to a hip injury he aggravated at Wimbledon but despite being demoted from the number one position, could yet return to the summit of the ATP standings. The Scot has won just one title this year in Dubai in an otherwise poor campaign.
Whichever player prevails at the US Open will be assured of being the number one player heading into the closing months of the season, yet they will come under pressure from a raft of young players including Alexander Zverev, Nick Kyrgios and recent Cincinatti champion Grigor Dimitrov.
With Nadal already in prime position, there are a number of different scenarios that can see him remain at world number one. Put simply, outperforming both Federer and Murray will be good enough to remain at the summit of the men's game.
The 31-year-old could also remain on top if he crashes out anywhere between the third round and the quarter-finals, provided Federer fails to reach the last four stage and Murray is under to advance to the final.
Should Nadal crash out at the semi-final stage - where he has twice lost in 2008 and 2009 - he is guaranteed to keep the world number one ranking if Federer fails to reach the final and Murray does not take the title.
As for Federer, the Swiss ace has to reach the quarter-final stage if he has any ambition of leapfrogging Nadal. Should both players reach that stage he must simply outperform the Balearic Islander.
In order to guarantee a jump to the number two ranking from Murray, Federer is certain to do so as long as the Briton fails to go past the semi-finals.
Murray may have been world number one for eight months but he faces a tough task to regain his place at the top of men's tennis. He must at least make the semi-finals to stand any chance of challenging Nadal or Federer and should he be joined at that stage by the pair, he must then go on to win the title.
Should he reach the semi-final stage - something he has only done once at a major this year - it could be good enough to capture world number one, but he must hope that Nadal suffers a first round exit and Federer fails to go past the quarter-final stage.
The 30-year-old could also regain top spot by making the final provided that Nadal does not go past the quarter-final stage and Federer exits in the semi-finals.