Serbia's Novak Djokovic has topped the year-end ATP world rankings for a record-equalling sixth time ©Getty Images

Novak Djokovic has topped the year-end Association of Tennis Professionals (ATP) world rankings for a record-equalling sixth time.

The Serbian previously finished the year as world number one in 2011, 2012, 2014, 2015 and 2018.

He equals the record set by America's Pete Sampras, who ended six straight years at the top of men's tennis between 1993 and 1998.

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

"I will also keep striving to be a better player, hopefully have more success and break more records in a sport I love with all my heart."

Djokovic enjoyed another successful year, despite the impact of the COVID-19 pandemic on sport, earning a record eighth Australian Open and 17th Grand Slam title in February.

He also helped Serbia to victory in the inaugural ATP Cup in January and finished as runner-up to Rafael Nadal at the French Open. 

At 33-years-old, Djokovic set a new record as the oldest year-end ATP number one. 

"To finish the year as number one 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."

Novak Djokovic was criticised for failing to socially distance during the Adria Tour, a tournament he organised across four countries in the Balkans in June ©Getty Images
Novak Djokovic was criticised for failing to socially distance during the Adria Tour, a tournament he organised across four countries in the Balkans in June ©Getty Images

It has also been a controversial year for Djokovic, however. 

He was disqualified from the US Open in September during his fourth round match against Spain's Pablo Carreno Busta, having accidentally hit a line judge with a ball after reacting to a dropped point in frustration. 

Djokovic was heavily criticised for organising the Adria Tour across four nations in the Balkans during the height of the COVID-19 pandemic in June.  

Players failed to socially distance and were shown dancing in a nightclub in Belgrade. 

The Tour was eventually cancelled after a number of cases in Zadar in Croatia, with Djokovic one of many tennis players to test positive for coronavirus. 

Djokovic also received criticism for creating a Professional Tennis Players' Association without female tennis players in August. 

Spain's Nadal, who has topped the year-end ATP rankings five times, finished second this year, with Austria's Dominic Thiem third. 

Djokovic is set to be presented with the year-end number one trophy at the ATP Finals in London, scheduled for November 15 to 22.