Roger Federer [ Images ] will end the year as world number one for the third time in a row after clinching a hat-trick of US Open [ Images ] titles, the ATP announced on Monday.

The 25-year-old Swiss, who beat American Andy Roddick [ Images ] 6-2, 4-6, 7-5, 6-1 for his ninth career Grand Slam on Sunday, has won eight titles so far this season, compiling a formidable 70-5 record.

His Flushing Meadows victory followed his titles at the Australian Open [ Images ] and at Wimbledon [ Images ]. He also reached the final of the French Open [ Images ], losing to Spain's Rafael Nadal [ Images ].

Federer is only the fifth player since the ATP rankings began in 1973 to be year-end number one three successive times.