German tennis star Alexander Zverev is set to reach the ATP world singles number one ranking for the first time in his career.

Zverev secured his ascent to the top spot after defeating Tallon Griekspoor of the Netherlands in the second round of the ATP Tour Erste Bank Open singles event in Vienna on October 29 (local time), advancing to the quarterfinals.

The ATP announced that Zverev will claim the number one ranking in the new rankings to be released on November 2.

Zverev will become the 30th player in history to reach the ATP world number one spot.

The ATP rankings were established in 1973.

Zverev becomes only the second German male player to reach world number one, following Boris Becker, who rose to the top on January 28, 1991.

"It's very special. The feeling of being at the top of the world is incredible," Zverev said. "It's different from winning a tournament, but knowing that 'number one' will be next to my name when the new rankings come out is a truly special feeling."

Jannik Sinner of Italy will be pushed down to second place as a result.

Sinner had held the number one spot since April 13.

Zverev has also secured the year-end world number one ranking for this season.

Additionally, at 29 years and six months old, Zverev will become the second-oldest player in history to reach world number one for the first time.

The record for the oldest first-time number one is held by John Newcombe of Australia, who reached the top spot at the age of 30 in 1974.

Zverev finally reaches the summit more than four years after first climbing to world number two.

At the start of the year, it would have been hard to imagine anyone other than Sinner or Carlos Alcaraz of Spain holding the world number one ranking, but an unexpected outcome materialized after both players missed significant periods due to injury and Zverev delivered valuable performances at major tournaments.

Zverev captured his first-ever major title at the French Open and subsequently triumphed at the US Open.

He finished as the runner-up at Wimbledon and reached the semifinals at the Australian Open.

He also posted strong results by finishing as runner-up at the Madrid Open, an ATP Masters 1000 event.

Zverev holds a 64-16 record this season, and besides Zverev, Daniil Medvedev of Russia is the only other player to reach the 50-win milestone this season.

Zverev has claimed two ATP Finals titles, two major titles, seven ATP Masters 1000 titles, and an Olympic gold medal in his career.

The number of active players who have held the world number one ranking has increased to five: Zverev, Sinner, Alcaraz, Medvedev, and Novak Djokovic of Serbia.

(Photo: AP, Yonhap News)