The key facts

  • Zverev beat Griekspoor 6-4, 7-5 and advanced to the Vienna tournament quarterfinals
  • He will become the 30th world No. 1 in history and the second-oldest debutant after Newcombe
  • The reason was Sinner's knee injury, which ended his season early

World No. 1 for the first time in his career

Alexander Zverev defeated Tallon Griekspoor 6-4, 7-5 on Thursday and advanced to the quarterfinals of the Vienna tournament, securing the top spot in the ATP rankings ahead of schedule, AFP reports. Although the German had previously finished the season at the top on guaranteed terms, in the absence of the current leader Jannik Sinner he will officially head the rankings for the first time in the updated lists next Monday. Thus, the 29-year-old Zverev will become only the 30th world No. 1 since the rankings were introduced in 1973.

Age and circumstances

When the new rankings are published, Zverev will be 29 years and 196 days old — making him the second-oldest debutant at the top spot after the Australian John Newcombe. His rival at the summit, two-time Grand Slam champion Sinner, decided to end his season in early October due to a knee injury, which opened the way to the throne for the German. Zverev himself won Grand Slam tournaments for the first time in 2026, taking the titles at Roland Garros and the US Open.

How the Vienna tournament unfolded

Over the course of the tournament, Zverev — who also has the ATP Finals coming up next month — defeated the Spaniard Martin Landaluce and Griekspoor. In his first-round match on Tuesday, he saved four match points against Landaluce, while against the 30-year-old Dutchman he won considerably more confidently: a break in the very first game, then the decisive break at 5-5 in the second set. The match featured a curious incident: when Zverev earned a match point, his smash knocked out part of the electronic scoreboard behind Griekspoor, and the umpire covered the faulty panel with a towel, after which Zverev sealed the victory with an ace.