How does Sinner's loss affect the battle for World No. 1?

Jannik Sinner was the heavy favorite to win the Canadian Open title, especially after the absences of Novak Djokovic and Carlos Alcaraz. However, the Italian fell in the quarterfinals to Andrey Rublev, failing to defend the title he won in 2023.

The Italian lost a significant number of points, narrowing the gap with Alcaraz and Djokovic, putting his hold on the top ranking at risk in the coming weeks.

For most of the year, Sinner had comfortably held the No. 1 spot, as none of his rivals could achieve results that brought them close enough to the Italian. However, with the start of the hardcourt swing, we may see changes at the top of the rankings.

Sinner is set to lose 800 of the 1,000 points he earned at last year's Canadian Open, bringing his total down to 8,770 points in the next ranking update. He will have just over a 300-point lead over Djokovic (8,460), with less than 1,000 points separating him from Alcaraz.

Starting Monday, the Cincinnati Open will take place without the defending champion Novak Djokovic, who will lose 1,000 points when the tournament concludes. As for Alcaraz, he finished as runner-up in 2023, so the only way for him to gain points is by winning the title. However, Alcaraz needs to reach the quarterfinals to secure the World No. 2 ranking, though he cannot yet aim for No. 1, as Sinner is not defending points in Cincinnati, and there is no mathematical way for Alcaraz to overtake him yet.

Cincinnati could be a crucial event for Sinner if he hopes to remain No. 1. Without defending points, it's a golden opportunity to widen the gap with his pursuers and limit the risk of what could happen afterward at Flushing Meadows. There, Djokovic is defending the title (2,000 points), while Alcaraz is defending the semifinals (720 points). Sinner, on the other hand, only reached the fourth round (180 points).

Given this, Djokovic currently has no chance of reclaiming the No. 1 spot, even if he defends his title at the US Open. Alcaraz, however, appears more threatening, having won the last two Grand Slams and looking like the player in the best form in recent months. He also knows what it takes to win the title at Flushing Meadows, having done so back in 2021.

Depending on their results in Cincinnati and the US Open, Alcaraz could potentially snatch the No. 1 spot from Sinner once the fourth Grand Slam of the year concludes. Sinner is guaranteed 8,590 points at the end of the US Open, plus any additional points he may earn in upcoming tournaments, while Alcaraz could reach a maximum of 9,640 points if he wins both the US Open and Cincinnati.