Second seed Novak Djokovic fought back from a set down to beat Croat Marin Cilic and secure a place in the Paris Masters semi-finals.
The Serb won 4-6 6-2 6-3 in two hours and 12 minutes despite being a set and a break down.
Djokovic lost the opening set and went 2-1 down in the third before immediately breaking back and then moving ahead at 5-3.
He will face either Roger Federer or Kei Nishikori in the semi-finals.
Djokovic showed frustration on court, aiming an outburst at his box before serving for the second set, and breaking his racquet after dropping serve in the third.
The 2018 US Open and Wimbledon champion is on a 21-match winning streak and has beaten Cilic in their two most recent meetings.
Djokovic, who has won four Paris Masters titles, will take the world number one ranking from Rafael Nadal on Monday.
Russian world number 18 Karen Khachanov beat fourth seed Alexander Zverev 6-1 6-2 in their quarter-final, setting up a last-four tie with Austrian sixth seed Dominic Thiem.
There were complaints from Zverev over noise coming from Khachanov’s box during the match, which finished in just over an hour.
French Open finalist Thiem came from a set down to beat defending champion Jack Sock 4-6 6-4 6-4 in two hours and 16 minutes.