The 43-year-old is level with Scot Stephen Hendry on 36 ranking titles and in top spot for the first time since May, 2010 - the oldest man to lead the rankings since Ray Reardon in 1983.
Asked about matching Hendry, O'Sullivan said: "That's one of the records that's nice to get, the centuries was nice, the 19 majors was nice. Those three records are great. The only one now is the world titles but I don't see that happening."
Earlier this month, O'Sullivan became the first player to compile 1,000 career century breaks en route to winning the Players Championship final in Preston.
As well as five world titles, O'Sullivan has won a record seven Masters titles and a record seven UK Championships -- the sport's Triple Crown tournaments known as the majors.
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Hendry tops the list for world titles with seven followed by both England's Steve Davis and Welshman Reardon on six.
O'Sullivan, who leapfrogged compatriot Mark Selby at the top of the world rankings, added: "It's crazy, really, I've probably only played about half the events that everyone else has played in to get to number one. It seems quite weird, really."
The Tour Championship is contested by the sport's leading eight players with a top prize of 150,000 pounds ($198,120.00).
(Writing by Ken Ferris; Editing by Ian Ransom)
