ATP TENNIS RANKINGS HISTORY - The No. 1 Players. From 1973 to 1999 the ATP utilized a 52-week Ranking System that now is used for the ATP Entry Ranking. The ATP Champions Race provides an easier-to-follow calendar-year race, culminating with a single year-end No. 1. The figures below highlight the achievements of the players over the past years. Since Ilie Nastase first reached No. 1 on the ATP Rankings on August 23, 1973, there have been 26 different players to reach the No. 1 ranking.