Half of the fourth round matches at the US Open are behind us, with two of the title favorites reaching the quarter-final on Sunday while Roger Federer and Novak Djokovic headline the Monday action. The defending champion Rafael Nadal has to reach the semi-final in order to secure the world number 1 position after the US Open and he is a win away from that, facing Dominic Thiem in the quarter-final after a win over Nikoloz Basilashvili in four sets.
Rafa is on 8400 points on the Live ATP rankings list, 1500 ahead of Roger Federer who will reduce the deficit to 1320 points if he beats John Millman tonight. If Nadal loses against Thiem and Federer goes all the way to win the first title in New York since 2008, the Swiss would become world number 1, although he has to pass some tough obstacles in order to achieve that.
2009 champion Juan Martin del Potro is on a way to reach the semi-final and defend points from 2017, looking to maintain his lead over Alexander Zverev in third place after another early exit for the German. Del Potro is on 5140 points at the moment while Zverev stands on 4890, missing a chance to pass the Argentinian as hasn't had too many points to defend.
Novak Djokovic will move even closer to Alexander if he beats Joao Sousa today and the Serb would become world number 4 if he tops Roger Federer in the projected quarter-final clash. If he goes all the way, Novak will become world number 3 and the battle for the year-end number position should be pretty much on in the rest of the season if that happens.
2014 winner Marin Cilic will also be in action today after a hard-fought triumph over Alex de Minaur in the previous round, standing 90 points behind Novak Djokovic and hoping to pass both Novak and Alexander with a deep run.
Grigor Dimitrov is seventh in the rankings but he failed to win a match in New York, suffering another early exit to Stan Wawrinka and standing on 3755 points, just 90 more than Dominic Thiem who will pass him if he beats Nadal in the quarters.
The last year's finalist Kevin Anderson has lost to Thiem in the fourth round and he could leave the Top 10 if both John Isner and David Goffin win their next matches. Isner will play in the quarter-final of the home Major for the first time since 2011 and he could pass Dimitrov, Thiem and Anderson with a win against Juan Martin del Potro in the quarters.
David Goffin is ranked just outside the Top 10 and he should be ninth if he manages to beat Marin Cilic tonight. Overall, there are only 320 points separating Grigor Dimitrov, Dominic Thiem, Kevin Anderson, John Isner and David Goffin and it should be interesting who will emerge at the top after the US Open.
Fabio Fognini, Diego Schwartzman and Stefanos Tsitsipas are already out and Kei Nishikori will pass the latter two with a triumph against Kohlschreiber in the fourth round, standing as the last active player at the US Open in the Top 35.
ATP Live rankings list before the remaining fourth round US Open matches:
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