Although Rafael Nadal did not make it beyond the group stage of last week’s ATP Finals in London, Novak Djokovic’s failure to reach the semi-finals meant Nadal closed the year with 9,985 points, 840 clear of the Serb.
The Spaniard was confirmed as the year-end world number one for the fifth time after the ATP published its season-closing rankings on Monday.
Nadal draws level with rivals Roger Federer and Djokovic, who have also finished the year in top position five times, and one behind six-time end-of-year number one Pete Sampras.
Nadal and Djokovic have been the two dominant players this year after winning two Grand Slam titles each.
Djokovic won the Australian Open and Wimbledon, while Nadal claimed Roland Garros and the US Open.
Roger Federer finishes the season at number three spot for the second year running. The tennis superstar, who turned 38 in August, has limited his participation in events around Grand Slams.
He got to the semi-finals of the French Open, where he lost to the eventual winner Nadal. He also reached the quarter-finals at Flushing Meadows, where he lost to world number 20 Gregor Dimitrov.
At Wimbledon, he lost an epic final against Djokovic, the first to be decided by a tie-break in the fifth set, suggesting there are hopes of a 21st major title in the 2020 season.
Dominic Thiem, who took a set off Nadal in the final of Roland Garros, is now number four after reaching the final of the ATP Finals, where he lost to Stefanos Tsitsipas.
The 21-year-old Greek closes the year at number six, just behind Daniil Medvedev, after his victory in London.
British Andy Murray started the year ranked at 240 and the prospect of retirement.
As he struggled with surgery on a hip injury and the subsequent recuperation he had slipped to 503 in September before a dramatic return to the courts, which produced a remarkable victory at the European Open in Antwerp, lifted him to a year-end 126.
ATP year-end rankings as of November 18:
1. Rafael Nadal (ESP) 9,985 pts
2. Novak Djokovic (SRB) 9,145
3. Roger Federer (SUI) 6,590
4. Dominic Thiem (AUT) 5,825 (+1)
5. Daniil Medvedev (RUS) 5,705 (-1)
6. Stefanos Tsitsipas (GRE) 5,300
7. Alexander Zverev (GER) 3,345
8. Matteo Berrettini (ITA) 2,870
9. Roberto Bautista (ESP) 2,540
10. Gaël Monfils (FRA) 2,530
11. David Goffin (BEL) 2,335
12. Fabio Fognini (ITA) 2,290
13. Kei Nishikori (JPN) 2,180
14. Diego Schwartzman (ARG) 2,125
15. Denis Shapovalov (CAN) 2,050
16. Stan Wawrinka (SUI) 2,000
17. Karen Khachanov (RUS) 1840
18. Alex De Minaur (AUS) 1775
19. John Isner (USA) 1770
20. Grigor Dimitrov (BUL) 1747