On the Association of Tennis Professionals' rankings released in 1973, who was the first No.1 ranked player?

The ATP Rankings are the Association of Tennis Professionals' (ATP) merit-based method for determining the rankings in men's tennis. The top-ranked player is the player who, over the previous 52 weeks, has garnered the most ranking points on the ATP Tour. Points are awarded based on how far a player advances in tournaments and the category of those tournaments.

Most players accepted the ATP Rankings, but there was controversy initially about what they were for. There was a great deal of conversation and tweaking during the formative years as to the weight of the various tournaments and even the weight of the rounds in the tournaments. The prize money per round was also debated in conjunction with the ranking points. But all the players were on the same page as to the importance of it for the game.

Romanian Ilie Năstase (born 19 July 1946) was the first No. 1 on the ATP Rankings, when the ATP established the new world ranking system on 23 August 1973. Nicknamed ‘Nasty’, the right-hander once said, “The player who wants to conquer the summit cannot afford to be kind... He must want to kill". The Romanian spent 40 straight weeks in the top spot until 3 June 1974, when he was replaced by John Newcombe of Australia.

Năstase won seven Grand Slam titles: two in singles, three in men's doubles and two in mixed doubles. He is the first male player to have won a French Open title without dropping a set (1973).