DEFENDING champion Roger Federer put an end to American hopes of a fairy tale victory for Andre Agassi with a four-set victory in the US Open final. The world No 1 Federer, won 6-3 2-6 7-6 (7-1) 6-1 to claim the sixth Grand Slam title of his career. The Swiss had looked in serious trouble at a break down in the third but hit back immediately. The world's top ranked player found his best form in the tie- break before sweeping through the fourth set to victory. "For me this was the most special Grand Slam final in my career," said Federer afterwards. "To play against Andre in New York, it's a dream. I had to play my best match and I did it again in the final. I don't know how I do it." Agassi admitted, "It's been a tough road but Roger played way too good in the final." Agassi, the former top ranked tennis player, congratulated the 24-year-old Federer on his performance and victory. At 35, Agassi was the oldest finalist since a 39-year-old Ken Rosewall won just two games in losing to Jimmy Connors in 1974. Agassi's future has been the subject of much discussion and he sounded like he may be signing off when he said: "Thank you New York, it's been a great 20 years." The day before the men's final, Belgium's Kim Clijsters finally ended her search for a Grand Slam title as she beat Mary Pierce of France to win the US Open women's title. The Belgian dominated from the outset, breaking three times in the first set and twice in the second on her way to a 6-3 6-1 win. Clijsters then leapt into the crowd to celebrate with her family and coach. "It's very hard to believe and an amazing feeling to have," she said. "After being out for so much of last year it's a little bit more special." As the winner of the summer's US Open Series, Clijsters doubles her prize money to $2.2 million. Clijsters had lost in four Grand Slam finals and missed much of 2004 with a career-threatening wrist injury. But she has returned better than ever this year and claimed her seventh title of 2005 with her 17th consecutive win. Pierce reached the French Open final in June but suffered a humiliating defeat then. The French described the winner Clijsters as a 'great girl.' "She's a champion. She's been No 1 in the world, now she has a Grand Slam title to her name. I'm happy for her," Pierce said afterwards.