The ATP player who was the first ever official world number one and won seven Grand Slams in his career

Alexander Zverev has the opportunity to achieve the world number one ranking for the first time in his career.

The German superstar, who has won two Grand Slam titles this year, is guaranteed to end the 2026 season in the top spot.

Zverev will claim the world number one ranking for the first time in his career if he advances to the Vienna Open quarter-finals.

The German opened his Vienna Open campaign on Tuesday, beating Martin Landaluce in a close three-set contest. As a result, Zverev needs to win just one more match to be crowned as the world number one.

With Zverev’s historic achievement fast approaching, let’s take a look back at the player who became the first official world number one in 1973.

Ilie Nastase became the first official world number one in 1973

Ilie Nastase, a seven-time Grand Slam champion across singles, doubles and mixed doubles, assumed the world number one ranking in singles on August 23, 1973.

Nastase rose to the pinnacle of men’s tennis following an exceptional 12 months on the professional circuit, during which he had captured Grand Slam titles at the 1972 US Open and 1973 French Open.

Nastase also won the 1972 Tour Finals, successfully defending his title from 1971.

The Romanian star held the position for 40 weeks before surrendering the top spot to seven-time major singles champion John Newcombe.

With 40 weeks to his name, Nastase has spent the 17th-longest time period as the world number one among all players since 1973.

A further 27 players have achieved the world number one ranking since Newcombe.

Alexander Zverev will become the 30th player to achieve world number one status when he claims the top position later this year.

Player

Weeks as world number one

Novak Djokovic

428

Roger Federer

310

Pete Sampras

286

Ivan Lendl

270

Jimmy Connors

268

Rafael Nadal

209

John McEnroe

170

Björn Borg

109

Andre Agassi

101

Jannik Sinner

95

Lleyton Hewitt

80

Stefan Edberg

72

Carlos Alcaraz

66

Jim Courier

58

Gustavo Kuerten

43

Andy Murray

41

Ilie Năstase

40

Mats Wilander

20

Daniil Medvedev

16

Andy Roddick

13

Boris Becker

12

Marat Safin

9

John Newcombe

8

Thomas Muster

6

Carlos Moyá

2

Patrick Rafter

1

Alexander Zverev

0 [guaranteed to become world number one]

If Zverev achieves the top ranking in Vienna, he is guaranteed to hold the top spot for at least nine weeks.