Andy Murray says he feels “very proud” to become the first British singles player to be world number one since computerised rankings began in 1973.
The Brit, 29, needed to reach the final of the Paris Masters to replace Novak Djokovic – and did so when Milos Raonic pulled out before their semi-final.
Murray won Wimbledon and Olympic gold in 2016, reached 11 finals in 12 events and won a personal record 73 matches.
“I never thought I’d be number one in the world,” he told BBC Sport.
“It’s been many years of work to get here. It’s been such a difficult thing to do because of how good the guys around me have been.”
Murray, who has won three Grand Slam titles, two Olympic gold medals and helped Britain win the Davis Cup in 2015, will be officially confirmed as world number one when the revised rankings are released on Monday
“The year I’ve had to have to barely get there has been unbelievably difficult. I’ve had to work extremely hard.”