The Serb triumphed at the season-ending tournament in Turin
Novak Djokovic joined Roger Federer as a record six-time winner of the ATP Finals after the Serb defeated world number four Casper Ruud in Sunday's title match at the season finale in Turin.
After emerging unbeaten from the round-robin group stage and defeating Taylor Fritz in the semifinals on Saturday, Djokovic again drew upon his experience and some scintillating tennis to break the resolve of the 23-year-old Ruud.
Djokovic prevailed 7-5 6-3 at the Pala Alpitour arena, landing him a payday of almost $4.75 million as an unbeaten tournament champion.
After some grueling contests during the week in Turin - including his three-hour battle with Russia's Daniil Medvedev in the group stage - Djokovic appeared to be physically struggling during the first set against Ruud and was seen with his hand shaking as he wiped his face during a changeover.
But the 21-time Grand Slam champion held it together, making the breakthrough on the Ruud serve in game 12 to win the opening set, having spurned three previous break-point opportunities.
The Serb further seized the initiative in set two as he broke Ruud's serve in game four, before seeing out the set and the match.
Ruud had comfortably overcome Russian rival Andrey Rublev in the semifinals, but failed to engineer a single break point opportunity on the Djokovic serve during the contest. The Norwegian remains winless in four career matches against Djokovic.
While the title was a sixth at the ATP Finals for Djokovic, it was his first at the event since 2015.
It means Djokovic, 35, has capped the year in style, following a season which began with his unsavory deportation from Australia but later included the highs of his Wimbledon win and ATP titles at the Rome Masters, Tel Aviv, and Astana.
Having been cleared for a return at the Australian Open in January after his visa ban was recently overturned, Djokovic will be among the firm favorites once the action begins in Melbourne, as he goes in pursuit of a record-extending 10th crown at the tournament.