NEW YORK (AFP) - Defending champion Rafael Nadal and world number four Andy Murray were among the stars left in limbo Tuesday as rain washed out all play at the US Open. Nadal no stranger to weather disruptions after repeated delays prolonged his path to completion of a career Grand Slam here last year had been scheduled to face Luxembourgs Gilles Muller for a quarter-final berth. Murray had been set to open play on the Arthur Ashe Stadium against Donald Young at 11am, but about 2 1/2 hours after that officials of the US Tennis Association announced they were cancelling both the day and night sessions. Cancelled, was fourth-seeded Murrays succinct comment on the social networking site Twitter. On the eve of the tournament, Murray had expressed his surprise that the playing surfaces were not covered. I dont understand why they dont just have covers. I heard that if they have covers, something to do with the paint on the court and the moisture... the court can lose color or something, said Murray. The USTA issued a jam-packed order of play for Wednesday, featuring the four mens last-16 matches postponed from Tuesday and two mens quarter-finals and all four womens quarter-finals. Other mens fourth-round matches postponed from Tuesday were fifth-seeded David Ferrers clash with Americas former world number one Andy Roddick, and 12th-seeded Frenchman Gilles Simon against 28th-seeded American John Isner. Two womens quarter-finals rescheduled from Tuesday were world number two Vera Zvonareva against ninth-seeded Australian Samantha Stosur and 26th-seeded Italian Flavia Pennetta against unseeded German Angelique Kerber. Those are now on the Wednesday slate along with world number one Caroline Wozniacki v Andrea Petkovic and Serena Williams v Anastasia Pavlyuchenkova. For Stosur, an extra day off might be a respite after two gruelling encounters. Stosurs three-hours, 16-minute third-round victory over Nadia Petrova was the longest womens singles match recorded at the US Open since the tiebreak era began in 1970. On Sunday she dropped an epic second-set tiebreaker but recovered to beat Russian Maria Kirilenko 6-2, 6-7 (15/17), 6-3. Five-time champion Roger Federer was among the four men who beat the weather to lock up quarter-final berths on Monday. World number one Novak Djokovic, seeking to add a first US Open crown to the Australian Open and Wimbledon titles he has already claimed this year, set up a last-eight clash with friend and Serbian Davis Cup teammate Janko Tipsarevic. Theyll be second up on the Ashe court after Nadal and Muller. Federer will face 11th-seeded Frenchman Jo-Wilfried Tsonga the man who rallied from two sets down to shock the Swiss great in the Wimbledon quarter-finals. Federer didnt get on court until shortly before midnight on Monday, and misty rain was falling by the time he completed his 6-1, 6-2, 6-0 demolition of unfortunate Argentinian Juan Monaco. Federer was pleased to be home and dry with his quarter-final berth, especially with Tsonga already through. It would have been a competitive advantage for Tsonga if I wouldnt have finished today or not even had a chance to play, said Federer, whose clash with Tsonga is now scheduled to be the last match of Wednesday night. Federer said he and his fellow players were used to coping with erratic schedules. Its crazy how our schedules change all the time, he said. As tennis players, it makes it extremely difficult to be on your A game every single day. Rain has bedevilled the tournament in recent times with the mens final, scheduled for the last Sunday of the fortnight, carried over to the Monday for the last three years. The first week of the US Open had been played out in bright sunshine although the schedule was tweaked on the opening Monday after the venue sustained minor damage when Tropical Storm Irene lashed new York. Downpours again sparked questions over the decision by the Flushing Meadows authorities not to follow the lead of the Australian Open and Wimbledon in building a retractable roof over its main court.