Andy Murray found his path to the US Open title eased somewhat when organisers decided to extend the tournament until Monday for the fourth successive year.
But he still faces a major battle, starting with a quarter-final clash against John Isner tonight.
It has been an extra- ordinary couple of days here at Flushing Meadows, where the issue of player power has taken centre stage.
On Wednesday, Rafael Nadal, Murray and Andy Roddick confronted tournament ref-eree Brian Earley about the decision to send them out on court in damp conditions, while Earley was also at the centre of attention yesterday.
This time water seeping through the court on Louis Armstrong Stadium was the problem, with the TV cameras capturing an angry Roddick berating Earley and then pushing through a move to Court 13 to complete his win over David Ferrer.
Amid all the various player complaints, the issue of the scheduling at the US Open, the only Grand Slam to hold the men's semi-finals and final on consecutive days, has been to the fore.
Two days of rain left the eventual finalist in the bottom half of the draw facing four matches in as many days before the organisers agreed to give them their wish.
The men's and women's semi-finals will now be played tomorrow, with the women's final on Sunday at 4pm and the men's final at the same time the following day.
Nadal said: "The problem is we need to have the right representation in these tournaments. Things like this cannot happen. Having the semi-finals on Saturday is something crazy for the players."
Murray, who wasted little time in defeating an erratic Donald Young 6-2, 6-3, 6-3, was the most outspoken of all the leading men and he called on the players to form their own union.
He said: "The players I think need to have more of a voice, and the only way to do that is by starting a player union and coming to an agreement with tournaments and the ITF (International Tennis Federation). Because, if not, the same things will keep happening and nothing will change."
The difficulty of securing a consensus among players all with their own interests was highlighted by world No.1 Novak Djokovic's response to the changes, the Serb unhappy because of the impact on next week's Davis Cup ties.
Despite the problems, the big names all came through, with Murray setting up a last-eight clash against 6ft 9in American Isner, who made it nine wins in a row with a four-set victory over Gilles Simon, while Nadal will meet Roddick.
Djokovic was the first man to advance to the semi-finals when friend and compatriot Janko Tipsarevic retired in the fourth set with a leg injury after a lengthy tussle.
He will face Roger Federer after the world No.3 avenged his defeat by Jo-Wilfried Tsonga at Wimbledon with a 6-4, 6-3, 6-3 victory in the night session.
Federer weighed into the debate about the scheduling by calling on the tournament to play the first round over only two days and scrap 'Super Saturday', which has the men's semi-finals and women's final played on the same day.
Williams wary of Wozniacki's fighting spirit
World No.1 Caroline Wozniacki and favourite Serena Williams will play a blockbuster semi-final tomorrow after both came through their delayed quarter-final clashes.
The pair had contrasting matches, with Williams struggling in the first set against Anastasia Pavlyuchenkova before achieving a 7-5, 6-1 win, while Wozniacki survived a fightback from Andrea Petkovic to triumph 6-1, 7-6 (7/5).
The victor will be a clear favourite to lift the trophy, and Williams, who has won their previous two meetings, talked up the qualities of her opponent.
She said: "I think Caroline is a very consistent player, both on the court and in playing tournaments and doing well and winning.
"That's pretty much what it takes to be the best. She never gives up.
"Also, she's moving really fast. She's running every ball down. That's a great weapon to have as well."
The other semi-final will be between ninth seed Samantha Stosur and unseeded German Angelique Kerber.
British boys ease through
Three British players, Oli Golding, George Morgan and Kyle Edmund, have reached the quarter-finals of the boys' singles at the US Open.
Golding beat No.3 seed Bjorn Fratangelo, 7-5, 3-6, 6-3, while Edmund, in his first US Open, defeated Filip Peliwo 6-2, 3-6, 6-1. Morgan hammered Robin Kern 6-2, 6-2.