Djokovic, Nadal and Phil Collins kick-off US Open

Novak Djokovic and Rafael Nadal get their US Open campaigns under way Monday in the shadow of Arthur Ashe Stadium's spectacular $150 million retractable roof and alongside rock music legend Phil Collins.

Defending champion Djokovic and fellow two-time winner Nadal come into the season's final Grand Slam with injury concerns.

World number one Djokovic, the 2011 and 2015 champion, admits he is "not 100 percent" after suffering a wrist injury on the eve of the Olympic Games where he was a shock first-round loser.

The 29-year-old has also said "personal problems" contributed to his third-round exit at Wimbledon which ended his hopes of going on to capture the first calendar Grand Slam since 1969.

Nadal, meanwhile, is also battling the effects of a left wrist problem which forced a mid-tournament withdrawal from the French Open and sidelined him until the Olympics where he was a gold medal winner in the men's doubles.

The injury concerns, combined with the absence for the first time since 1999 of five-time winner Roger Federer, have put 2012 champion Andy Murray in the position of favourite.

Djokovic starts his bid for a third major of 2016, and 13th of his career, against Polish giant Jerzy Janowicz, who was a Wimbledon semi-finalist in 2013.

A serious knee injury has limited Janowicz to just six matches all year and seen his world ranking collapse to 228.

Nadal, the 2010 and 2013 champion in New York, tackles Denis Istomin of Uzbekistan.

The Spaniard has a 4-0 career record over world number 107 Istomin, including a win over the Russian-born player at the 2010 US Open.

Nadal closes the daytime session on Ashe while Djokovic starts the evening entertainment.

In between, the tournament will stage its opening ceremony with Collins, making his first concert appearance in six years, headlining the occasion by reprising his "In the Air Tonight" hit.

Play on the cavernous Ashe stadium starts at 1500GMT with 2015 women's runner-up Roberta Vinci, the Italian seventh seed, facing Germany's Anna-Lena Friedsam.

Vinci stunned Serena Williams in the semi-finals in 2015 before losing the championship match to Italian compatriot Flavia Pennetta who retired in the immediate aftermath of her first and only Grand Slam win.

World number two Angelique Kerber, the Australian Open champion who can dethrone six-time US Open winner Williams as world number one in New York, opens against Polona Hercog of Slovenia.

Action on Louis Armstrong Stadium starts with 2014 champion Marin Cilic against Rogerio Dutra Silva of Brazil.

That's followed by former major winners Francesca Schiavone and Svetlana Kuznetsova.

They played the longest ever women's match at the Australian Open in 2011, a four-hour 44-minute epic won by Schiavone after saving six match points.

French Open champion Garbine Muguruza, the Spanish third seed, faces Belgian qualifier Elise Mertens.

The brand new Grandstand arena kicks off with Taylor Townsend of the United States facing two-time runner-up Caroline Wozniacki of Denmark.

Serena Williams and 2012 champion Andy Murray will get underway on Tuesday.