ATP Tour

Sinner, Alcaraz & the return of a rare youth-led No. 1 race

The 2025 ATP Tour season ended with a statistical clarity rarely seen in the modern era: Only Jannik Sinner, 24, and Carlos Alcaraz, 22, held the No. 1 spot in the PIF ATP Rankings at any point.

With both players under 25 and splitting the sport’s four majors between them, the season stands as a clear marker of a new phase in the ATP No. 1 Club. Their year-long control at the top places 2025 among the youngest dual-player No. 1 seasons in ATP history.

That distinction becomes clearer in the context of previous decades. Since the inception of the PIF ATP Rankings in 1973, only a small number of seasons have featured all No. 1s being under age 25, with 2025 entering alongside some of the sport’s most formative generational handovers.

ATP Tour seasons when all No. 1 players were under age 25 (since 1973) 

_{*Ages listed reflect the oldest age each player reached while holding the No. 1 spot during that season}

What links these seasons is how sharply they highlight moments of transition — periods in which emerging champions took command of the sport earlier than expected. The 2025 season fits squarely in that lineage, echoing shifts like Bjorn Borg - John McEnroe in 1980 or the early Pete Sampras years in the 1990s.

The comparison with the Big Three era adds essential perspective. Roger Federer, Rafael Nadal, and Novak Djokovic produced one of the most dramatic and competitive Lexus ATP Head2Head trilogies in tennis history, but their rivalry rarely intersected at No. 1 while they were still so young.

Federer holds the record for the most consecutive weeks at No. 1 (237 between 2004-08), Nadal finally broke through in 2008 at age 22, and Djokovic took over in 2011 at 24 — but sustained, two-player battles for No. 1 between them did not arrive until largely after age 25.

That is what sets 2025 apart. Having two multi-major champions contesting the No. 1 spot throughout the same season at ages 22 and 24 is statistically rare and historically significant. The last time a pair this young shared control at the summit was over two decades ago in 2004, when 23-year-old Federer and 21-year-old Andy Roddick dominated.

Rivalries such as that of Sinner-Alcaraz have historically signalled pivotal shifts in the sport. Borg and McEnroe defined the early 1980s with intense battles that often decided the No. 1 ranking, while Andre Agassi and Sampras carried the torch in the 1990s with contrasting styles and personalities shaping multiple seasons at the top.

*Research for this story was provided by Jon Jeraj