Andy Murray is now one match away to snatch the World number one title from Novak Djokovic, after beating Tomas Berdych in Paris Masters quarter-final 7-6 7-5.
Murray rallied from 4-6 in tie break of the first set against the Czech, to snatch the first set, winning the tight game 11-9.
In the second set, a determined Murray broke Berdych in the first game and went on to win his own game via love. He eventually won the set 7-5.
Djokovic who had held the world title since 2014, crashed out of the Paris Masters in straight sets to Marin Cilic earlier on Friday.
Djokovic, who was chasing a fifth title in Paris, was beaten 6-4 7-6 (2), his first defeat to the big-serving Croat in 15 matches.
Djokovic, who needed to reach the final to guarantee keeping Murray at bay, saved two match points at 6-5 in the second set, the latter with a superb forehand cross court, but was soon facing a losing battle in the tiebreak.
Cilic, who clinched his spot in the World Tour Finals on Thursday, raced into a 5-2 lead before a huge serve set up four more match points.
He was soon celebrating after swiping away a mid-court forehand to claim victory in one hour 45 minutes.
At the moment, Djokovic has 12,900 points in the ATP Ranking, while Murray has 10,985.
But having crashed out of the Paris Masters, the Serb will lose 2,300 points, while all Murray needs now is a victory in the semi-final against Milos Raonic who beat Jo-Wilfried Tsonga 6-2 7-6 in the late late quarter-final match on Friday.
The victory in the semi-final will give Murray 800 ranking points, which will take him to 11,785, while, Djokovic slumps to 10,600 points, effectively conceding the first spot to the hard-fighting Scotsman.
Murray told Skysport after the match; “I have never been in that position of playing for the world number one spot before so I don’t know how I will deal with it tomorrow.
“It can be tough for the 45 minutes or so before the match, but it was not my goal to get to world number one this year. I am just pleased with how I am playing over the latter half of this season.”
*Updated with the result of Milos Raonic v Tsonga match.