Much like the dominance once shared by Roger Federer, Rafael Nadal, and Novak Djokovic, men’s tennis now finds itself defined by the rivalry between Carlos Alcaraz and Jannk Sinner. Both players broke onto the scene as the Big 3’s era was winding down, facing only Djokovic and Nadal at the tail end of their careers.

That timing has allowed them to bypass the psychological hurdles many of their predecessors faced, arriving with fresh energy, immense athleticism, and a brand of tennis that has captivated fans around the world.

Still early in their careers, Alcaraz and Sinner have already produced classics that will be remembered for decades, including this year’s Roland Garros final and their Wimbledon showdown just weeks later.

Their rivalry nearly added another chapter in Cincinnati, but after Alcaraz raced to a 5–0 lead in the opening set of the Masters 1000 final, Sinner retired, handing the Spaniard the title.

Jannik Sinner of Italy meets with Carlos Alcaraz of Spain and umpire Mohamed Lahyani to retire from the Cincinnati Open final. (Dylan Buell/Getty Images)

What Alcaraz needs to become No. 1 again

The Cincinnati crown gave Alcaraz 1,000 ranking points while Sinner lost 550, narrowing the gap but leaving the Italian at the top for now. That balance could shift quickly when the final Major of the year begins in New York, running from August 24 to September 7.

Alcaraz has little to defend at the US Open after falling in the second round last year, while Sinner will be defending his championship. That means the math is simple: if Alcaraz wins the US Open — regardless of how far Sinner advances — he will return to World No. 1.

What happened with the US Open mixed doubles?

This year, the US Open introduced a new format for mixed doubles, pairing top ATP and WTA singles players. Sets are now played to the best of four games, creating faster matches with shorter duration.

However, both Alcaraz and Sinner are no longer in the tournament. The Italian withdrew alongside his partner Katerina Siniakova for obvious reasons, while the Spaniard lost in the first round with Emma Raducanu, falling to Jack Draper and Jessica Pegula. This means both players can now fully focus on the final Major of the year.