Federer took over the top spot after defeating Andy Murray in the final at Wimbledon. It was a record-tying seventh Wimbledon championship and pushed Federer's record number Grand Slam titles to 17.
He was the silver medalist -- to Murray --- at the Olympics and came back with a win at Cincinnati for a record-tying (matching Rafael Nadal) 21st Masters title. That also ran his 2012 record to 56-7 with six championships.
He has 12,165 ranking points and the ATP says Federer will be on top of the rankings after the men's singles final Sept. 9 in New York. That will extend the record of 293 weeks he's spent at No. 1.
Defending U.S. Open champion Novak Djokovic, ranked No. 2, has 11,270 points. Nadal, who lost the 2011 U.S. Open final to Djokovic, is No. 3 with 8,715.
Nadal isn't in New York due to a knee problem and that could open the door for No. 4 Murray, still seeking a first Grand Slam championship, to move up in the rankings. He has 7,290 points.
David Ferrer is fifth with 5,375 points followed by Jo-Wilfried Tsonga at 4,835 and Tomas Berdych with 4,200. Juan Martin del Potro (3,620) sits eighth with Janko Tipsarevic in ninth at 3.295 and John Isner (2,880) at No. 10.