Andy Murray will become the world number one on Monday after his Paris Masters opponent Milos Raonic withdrew from the competition.
Murray was set to face Raonic in the semi-finals but his opponent was forced to retire from the tournament after suffering a tear to his right quad.
Speaking in Paris, Raonic said: "Yesterday I started feeling something in my leg, this morning I had trouble getting out of bed.
"I did an MRI and they found I have a grade one tear in my right quad and I am not able to compete.”
The injury means that the Canadian will not be able to participate in the season-ending Tour finals in London, however, the result means that Murray advances to the final, which he needed in order to secure the No.1 spot.
Djokovic’s lead at the top spot, which he has occupied since June 2014, seemed unassailable for a while, especially given the fact that the Serbian became the first ever holder of all four grand slam titles at the same time in June.
However, with Djokovic’s defeat in the quarter-finals in Paris, and Murray’s commanding form this year which saw him win Wimbledon, Olympic Gold and four other titles, while only losing just three matches in the process, means that Murray has now managed to overtake Djokovic.
He will now play John Isner in tomorrow's final after the American saw off Cilic 6-4 6-3 in Saturday's other semi-final, and will be officially confirmed as world number one after the rankings are revised and released on Monday.
Murray, who turned 29 in May, has now become the second oldest player to reach number 1 for the first time after John Newcombe in 1974.
The Scot has received plenty of praise on Twitter for famous faces and fans alike. Here are a few of the best tweets: