New York:Rafael Nadal, of Spain, will be the top seed in a grand slam for the first time in his career at this year's US Open.
The newly-crowned world No. 1 will be followed by No. 2 Roger Federer of Switzerland, No. 3 Novak Djokovic of Serbia, No. 4 David Ferrer of Spain and No. 5 Nikolay Davydenko of Russia, said the tournament which released its seedings on Tuesday.
After spending 160 consecutive weeks ranked second, Nadal officially became the new world No. 1 on Monday - ending Federer's record reign of 237 straight weeks.
A 12-time Grand Slam champion, Federer was the top seed at the last 18 majors.
The highest-seeded American is No. 8 Andy Roddick, who won the event in 2003, and countryman James Blake is just a spot back as the No. 9.
Like the men's seeding, there were no major surprises in the women's draw, where top-ranked Ana Ivanovic is the No. 1, followed by Jelena Jankovic, Svetlana Kuznetsova, Serena Williams and Elena Dementieva.
French Open runner-up Dinara Safina is the No. 6, and Wimbledon champion Venus Williams is the seventh seed.
The most notable absence on the women's side is world No. 6 and 2006 champion Maria Sharapova, who announced earlier this month that she is skipping the event to recover from a shoulder injury.
All eyes will be on Nadal in Flushing Meadows as he attempts to become the first player since Rod Laver in 1969 to win the French Open, Wimbledon and the U.S. Open in the same year.
Anything seems possible for the 22-year-old these days, as he already has eight titles in 2008 - including Olympic gold in Beijing this past weekend - and an ATP-best 70-8 record.
Nadal defeated Federer in the French Open final for the third straight year and then ended the Swiss star's five-year reign at Wimbledon a few weeks later.
Federer is the four-time defending champion here.
Now-retired Justine Henin is the defending champ on the women's side, which means the last three winners will not be participating this year; 2005 champion Kim Clijsters also is retired.
The singles draws for the US Open will be announced on Thursday.