Andy Murray continues his chase for the No 1 spot and victory over Fernando Verdasco in the Paris Masters second round sees him draw closer.
The British tennis star who has a shot at overtaking Djokovic if he continues his fine form, won 6-3 6-7 (5-7) 7-5 in two hours and 29 minutes despite a patchy display.
Earlier, Djokovic beat Luxembourg’s Gilles Muller 6-3 6-4.
The Serb, 29, will retain his number one ranking – held for 122 weeks – if he reaches the final. If he doesn’t and Murray wins the title, he can wave the top spot goodbye.
The 29-year-old Scot faces Frenchman Lucas Pouille on Thursday, while Djokovic plays Bulgarian Grigor Dimitrov.
Victory over Verdasco means Murray, who secured his seventh title of the year in Vienna on Sunday, has won 53 of his past 57 matches.
“It was a tough match. Verdasco was going for his shots and serving huge,” the Scot said.
“When he was behind in games and even when I was getting the return back, he was dictating the points on his forehand and backhand. He hit a few lines with his backhand.
“I just had to fight at the end.”