Novak Djokovic (SRB)

World ranking: 1

Age: 26

Grand Slam singles titles: 6

Career prize money: $51,645,610

Best US Open result: Champion (2011)

Rundown: Top seed Djokovic arrives at the US Open once again under the radar with plenty of focus on the rejuvenated form of Rafael Nadal and with Andy Murray defending a Grand Slam title for the first time. Champion in 2011, Djokovic is bidding to reach the US Open final for a fourth successive year.

Rafael Nadal (ESP)

World ranking: 2

Age: 27

Grand Slam singles titles: 12

Career prize money: $56,910,697

Best US Open result: Champion (2010)

Rundown: Nadal continues to confound. After missing seven months to injury, he has returned to collect nine titles in 2013, including an eighth French Open. Suffered a shock first-round loss at Wimbledon, but has recovered well with back-to-back Masters triumphs in Montreal and Cincinnati.

Andy Murray (GBR)

World ranking: 3

Age: 26

Grand Slam singles titles: 2

Career prize money: $29,946,843

Best US Open result: Champion (2012)

Rundown: Having ended Britain's 77-year wait for a men's champion at Wimbledon, Murray finds himself in the unusal position of defending a major title for the first time after his breakthrough 12 months ago. Also the runner-up in 2008, Murray enjoys the raucous atmosphere of Flushing Meadows.

Roger Federer (SUI)

World ranking: 7

Age: 32

Grand Slam singles titles: 17

Career prize money: $77,775,114

Best US Open result: Champion (2004, 2005, 2006, 2007, 2008)

Rundown: Make-or-break time for Federer, who enters the tournament at seven in the world, his lowest ranking since October 2002. Has already been beaten 11 times this year, the 32-year-old has battled a recent back injury and a dent in confidence caused by his early exit at Wimbledon.

Juan Martin Del Potro (ARG)

World ranking: 6

Age: 24

Grand Slam singles titles: 1

Career prize money: $13,167,712

Best US Open result: Champion (2009)

Rundown: Del Potro stunned Federer to win the 2009 US Open but hopes of a new dawn were thwarted by a wrist injury which sent him off tour for most of 2010. Beaten by Djokovic in a thrilling Wimbledon semifinals but buoyed by the title in Washington, del Potro is the US Open's biggest dangerman.

(China Daily 08/24/2013 page16)