Novak Djokovic on Friday emulated childhood hero Pete Sampras by claiming the year-end world No.1 ranking for the sixth time.

The 33-year-old Serb was confirmed in the position after Rafael Nadal, the only man who could deny him top spot, opted not to play in the Sofia event next week.

Djokovic was also the season-ending world No.1 in 2011, 2012, 2014, 2015 and 2018.

He said, "Pete was somebody I looked up to when I was growing up, so to match his record is a dream come true."   

The Serb star, a winner of 17 Grand Slam titles, had already moved past Sampras' tally of 286 weeks in the top spot in September. 

Djokovic can go past all-time record-holder Roger Federer's mark of 310 weeks on March 8 next year. 

"To finish the year as No.1 is one of the most impressive achievements in our sport, one which requires sustained excellence across the season," said ATP chairman Andrea Gaudenzi. 

"To see Novak achieve this for the sixth time and match Pete's record is simply incredible, and he continues to cement his place in the history books." 

Djokovic has compiled a 39-3 winning season, picking up four titles – a record eighth Australian Open, Dubai, the Cincinnati tournament, which was staged in New York, and in Rome. 

However, he was disqualified from the U.S. Open for hitting a line judge with a ball before his bid to win a second Roland Garros ended in a tame defeat to Nadal in the final. 

Djokovic will attempt to secure a record-equaling sixth ATP Finals trophy in London from November 15. 

Meanwhile, Nadal stayed on track for a maiden Paris Masters title by beating fellow Spaniard Pablo Carreno Busta 4-6 7-5 6-1 on Friday, a result that gave Argentine Diego Schwartzman the last spot at the season-ending ATP Finals. 

(With input from agencies)