Rafael Nadal has secured ending the season as world number one after winning at the Paris Masters.
The Spaniard beat Hyeon Chung in the second round of the competition to confirm his place at the top of the ranking system, regardless of any future results until the end of the season.
The 31-year-old has risen from ninth at the start of the year via French and US Open victories.
He will play Uruguay's world number 36 Pablo Cuevas in the last 16.