Five-time defending champion Roger Federer and Dinara Safina will be the top-seeded players when the US Open gets under way on August 31.
The seedings for the tennis season's final major championship followed the ATP and WTA rankings.
Federer, a Swiss seeking his 16th major championship after wins at the French Open and Wimbledon this year, is followed by Britain's Andy Murray, Spain's Rafael Nadal and Serbia's Novak Djokovic.
Andy Roddick, the 2003 US Open champion who lost a five- set Wimbledon final to Federer in July, is the No. 5 seed and the only American man in the top 20. James Blake is the No. 21 seed and Sam Querrey is No. 22.
Safina, the French Open runner-up this year, never has won a major title or been to a final at the US Open.
Irishman Conor Niland faces up to Australia's Joseph Sirianni in his opening round match in the US Open qualifiers in New York today.
Veteran Sirianni, who was 34 last January and has been playing on the professional circuit since 1996, possesses a significant world ranking edge over the 27-year-old Irish player, the respective marks being 240 and 402.
However, Niland was placed at 263 up to last week when the 110 ranking points he earned for winning the ATP Challenger Tour event in New Delhi 12 months ago automatically dropped off.
The two players have met on one previous occasion, Melbourne-native Sirianni, currently seventh in the Australian national rankings,recording a 6-4 6-2 win in a Challenger event in Brisbane in 2007.
Sirianni won two matches in the Wimbledon qualifiers this year, but Niland will take encouragement from the fact that his Flushing Meadows opponent has been going through a barren patch in recent weeks, netting just one win out of his last seven matches stretching back to the beginning of July.
The Limerick man is making his debut in the final Grand Slam of the year — in fact, it will be his first visit to New York — but he is not lacking in experience of similar situations, having taken part in both the Australian Open and Wimbledon qualifiers in 2008 and 2009.
Niland will have to win three matches in order to nail down a place in the 128-strong main draw which starts next Monday.