The star trio ranked first at one stage during the year, the first time for them to make that during the same season.
Djokovic, who ended 2017 at No. 12, became the first player in history to finish No. 1 after ranking outside the top 10 in the previous season. At 31, he is also the oldest year-end world No. 1.
Five changes in top 10 can be found compared with that last year, including two newcomers, the sixth-ranked Kevin Anderson and No. 10 John Isner. Moreover, Djokovic made his way back to top 10 along with Juan Martin del Potro and Kei Nishikori.
For the first time since the ATP Rankings was introduced in 1973, players from five different regions of the world have been represented in the top 10, including six from Europe, and one each from Africa, Asia, North America and South America.
The ATP Rankings has witnessed the year-end top 10 from 10 different countries for the second time in three years.
The ATP year-end top 10 players are Djokovic, Nadal, Federer, Alexander Zverev, del Potro, Anderson, Marin Cilic, Dominic Thiem, Nishikori and Isner.
