Rafael Nadal, Andy Murray Cruise into Quarters [U.S. Open Tennis]

Spain's Rafael Nadal and Briton Andy Murray made up for lost time by demolishing their fourth round opponents in straight sets at the U.S. Open on Thursday to remain on course for a blockbuster semi-final showdown.

The pair needed around two hours each to charge into the quarter-finals when they were cleared to resume their matches after the rain and drizzle that washed out the last two days of the tournament was replaced by brilliant blue skies.

Nadal kept his title defense on track with a 7-6 6-1 6-2 victory over Luxembourg's Gilles Muller while Murray breezed past American wildcard Donald Young 6-2 6-3 6-3.

Tournament organizers were berated by players on Wednesday after they tried to make them play in the rain and there were more farcical scenes on Thursday because of damp patches on the Louis Armstrong Stadium court.

American Andy Roddick, who was among a group of players that angrily complained about court conditions on Wednesday, again confronted officials after resuming his round of 16 clash with Spanish fifth seed David Ferrer at Louis Armstrong.

The players returned to the locker room as staff tried in vain to dry the court with towels and a vacuum before the match was eventually moved to an outside court with seating for less than 600 spectators.

I'm baffled, I'm baffled. Find us a court, Roddick snapped at officials. At a certain point that has to take precedence over what people can watch.

The two-day delay forced officials to hastily rearrange the schedule in a bid to finish the tournament on time and avoid slipping into a third week for a fourth straight year.

Thursday's schedule, which was originally supposed to be just two men's quarter-finals, was increased to 10 matches; the two men's quarters; all four women's quarters, featuring Serena Williams and world number one Caroline Wozniacki; and four men's fourth round matches.

The men involved in the fourth-round clashes are the worst effected by the foul weather and they now face the daunting prospect of having to win four matches in four days to win the championship.

I'm pleased to get off and get some rest because it's a long few days ahead, said Murray, who will play either Gilles Simon or John Isner in the next round.

Nadal showed no signs of the cramping that caused him to collapse during his news conference after his last match as he overwhelmed Muller. The match resumed with Nadal trailing 3-0 but the Spaniard broke back and won the first set tiebreaker than ran away with the match.

He plays the winner of the Roddick-Ferrer match.