Medvedev's defeat against Kyrgios at the US Open has caused the Russian to cease to be world number 1 on September 12. With the loss of 1,820 points by the Russian Rafa Nadal, he is already number 1 'live' in the ATP Ranking, which is officially updated on September 12.
But to keep that number 1 on September 12 and not depend on anyone, Nadal should have reached the final of the US Open, something that will not happen, after his elimination at the hands of Frances Tiafoe in the round of 16. Despite this, he can still finish the tournament at the top of the rankings. For that to happen, Alcaraz and Ruud would have to lose in the semifinals or earlier. Nadal, 36, has not been number 1 in the world since February 2, 2020.
In the case of Carlos Alcaraz, if Nadal had prevailed in the round of 16, he would have to win the US Open to become the youngest number 1 in the history of the Pepperstone ATP Rankings at 19 years old. Now, after the elimination of the man from Manacorí, it is easier for him: if he reaches the final he would be the leader of the classification, the result would not matter.
Almost the same options that Casper Ruud has. The Norwegian would also have to be champion if Nadal had not been eliminated at the hands of Tiafoe. However, now he would also serve him with reaching the last round of the American championship to climb to the top of the podium.