Jannik Sinner is expected to lose his position as the world number one in men's tennis by the end of the season, according to several reports. Sinner currently holds 11,000 points in the ATP rankings, but by the time of the ATP Finals, he will lose 3,050 points, making it impossible for him to stay at the top. Alexander Zverev has already overtaken Sinner in the ATP Race, with 8,750 points compared to Sinner's 7,950, giving Zverev an 800-point lead. Zverev still needs to defend points from earlier tournaments, including 50 from Shanghai, 330 from Vienna, 400 from Paris, and 200 at the ATP Finals. Winning a title in Shanghai alone would not be enough to immediately push Sinner out of first place. The real shift in rankings could happen at the end of October or the beginning of November, when the large points from Vienna and Paris start to be removed from Sinner's total. This would significantly reduce his overall score, making it harder for him to retain his number one spot. Meanwhile, Carlos Alcaraz is the only other player still mathematically in the running for the top position. Before his Tokyo final, Alcaraz had 4,380 points in the Race, with the 330 points of the finalist already secured. He can still gain up to 170 additional points if he wins a title in Japan. Alcaraz's schedule still offers enough points to potentially surpass Zverev's 8,750 points in a near-perfect scenario. However, even in that case, his maximum score would only slightly exceed 8,800 points and could approach 9,000 if he also wins in Tokyo. This would require Alcaraz to win almost all remaining events up to Turin, while hoping that Zverev accumulates very few points. Ben Shelton currently has 4,430 points in the Race, compared to 4,380 for Alcaraz, but the American can no longer reach the 8,750 points accumulated by Zverev, even if he wins all remaining major events on his calendar.