Swiss champion Roger Federer on Monday dropped out of the top three men's singles rankings for the first time in over eight years.
The former World No 1 and holder of 16 Grand Slam titles was replaced by Briton Andy Murray after he sealed his third straight title in as many weeks at Shanghai on Sunday. Earlier, Murray was victorious at the Thailand Open and Japan Open during his 15-match winning streak.
Federer, who did not play in Shanghai, is now at No 4 -- his lowest ranking since 2003, a month before he won his first Grand Slam singles title at Wimbledon.
Murray, 24, has won 25 of his 26 matches since mid-August, his only defeat coming in the US Open semifinals to Spaniard Rafael Nadal, whom he beat in the Japan Open final.
He is now behind Serbia's Novak Djokovic and Nadal and is targeting to finish the year as World No 3 for the first time.
Murray has been ranked as high as No.2 in the world but his highest year-end finish is No 4.
In the women's singles, Denmark's Caroline Wozniaki continues to sit at the helm followed by Russia's Maria Sharapova and Victoria Azarenka of Belarus.