Novak Djokovic beat Norway's Casper Ruud 7-5 6-3 to collect a record-equalling sixth ATP Finals title on Sunday, earning the biggest paycheck ever in tennis - $4,740,300 - for completing the season-ending tournament unbeaten.

Novak Djokovic

Djokovic sealed victory in style with his ninth ace to collect the title for the first time since 2015 in front of a rapturous crowd.

"Got to stay focused the entire match, every single point, the momentum can switch to the other side really quickly," the Serbian said in a televised interview after the match.

"The fact that I waited seven years makes this victory even sweeter," he added as he matched Roger Federer's haul of six titles in the season-ending event.

The 23-year-old Ruud has enjoyed the best tennis of his career in 2022 and battled toe-to-toe with the 21-times major winner early on but produced two clumsy errors to hand Djokovic the break at the end of the first set.

Casper Ruud

Djokovic put his foot on the accelerator from there on, harnessing his mighty forehand to break Ruud in the fourth game of the second set.

The Norwegian threw everything he had at the veteran in a 36-shot penultimate rally but the Wimbledon champion was simply too sharp, outlasting his opponent in the marathon exchange and holding his arms out wide after clinching the title.