After defeating Tallon Griekspoor at the Erste Bank Open Thursday to guarantee he will climb to World No. 1 in the PIF ATP Rankings on 2 November, Alexander Zverev received a special welcome to the ATP No. 1 Club.
Thomas Muster, the lone Austrian who has reached World No. 1, joined Zverev on court in Vienna.
Muster climbed to the pinnacle of men's tennis in February 1996 and spent six weeks as World No. 1. The lefty remains the lone Austrian to achieve the feat.
Once Zverev officially joins Muster in the ATP No. 1 Club on Monday, they will represent two of the 30 members of the prestigious Club. The PIF ATP Rankings were created in 1973, more than 53 years ago.

Immediately after defeating Griekspoor, Zverev celebrated his special moment on court at the ATP 500 event.
The German's team joined him in the celebration, with father Alexander Zverev Sr. and best friend Marcelo Melo among those who partook in the special moment.

Zverev will look forward to seeing the No. 1 next to his name on Monday. But for now he will stay focused on the task at hand in Vienna. The top seed will face Arthur Fery in the quarter-finals.