Rafael Nadal celebrated the confirmation that he will finish the year as world number one by fighting through to the quarter-finals of the Paris Masters today.
The 31-year-old Spaniard had guaranteed the position for the fourth time in his career after his second round win over Hyeon Chung earlier this week.
And he maintained his momentum despite a tough test from Uruguay's world number 36 Pablo Cuevas, winning 6-3 6-7 (5) 6-3 in a match lasting two hours and 20 minutes.
Belgium's David Goffin sealed his place in the season-ending ATP World Tour finals despite crashing to a 6-3 6-3 defeat against French wild card Julien Benneteau.
Jack Sock's 7-6 (6) 6-3 victory over Lucas Pouille means the Frenchman can no longer catch Goffin, who therefore becomes the seventh player to guarantee his place in the Finals.
Juan Martin Del Potro continued his quest to reach the Finals as he moved into the Paris quarter-finals with a 7-5 6-4 win over Dutchman Robin Haase.
Del Potro's latest win takes him up to 10th place in the standings and just one more win away from moving ahead of Spain's Pablo Carreno Busta, who currently occupies the last qualification berth.
Del Potro will next face John Isner, who beat sixth seed Grigor Dimitrov 7-6 (10) 5-7 7-6 (3). There were also wins for Fernando Verdasco and qualifier Filip Krajinovic.