Novak Djokovic twice came from a break down to claim a sixth year-end No. 1 title on Sunday with his 7-6 (4), 6-7 (1), 6-3 defeat of Holger Rune at the ATP Finals.
He will mark a record 400th week in the top spot when the tournament concludes.
Victory in Turin – his 19th straight on the ATP – took more than three hours, fulfilling a Doomsday scenario of late-night finishes due to a start time of 9 p.m.
The Serb in the hunt for an eighth year-end event title and joined Yannik Sinner as an opening day winner in the group phase of the eight-man showpiece.
He has now won his last six at the season wrapup after claiming the title a year ago over Casper Ruud.
Djokovic was broken early in both the first and second sets by his 20-year-old Danish opponent but got the breaks straight back.
After the first two sets went into tiebreaks, the Serb finally cracked the door open and raced to victory in the third with a definitive break in the final game to love.
Rune fired 18 aces to 10 for Djokovic, producing 48 winners to his opponent’s 39.
Main photo:- Novak Djokovic celebrates as he retains ATP No. 1 position – by ATPTour.com