After 12 days without so much as a drop, a deluge is expected to strike the Big Apple today, with the expectation that Andy Murray will have to wait a third full day before he can contend for the grand-slam tournament final that has been his destiny since he drew his first C-shape with a racket.

The remnants of Tropical Storm Hanna are forecast to dump four inches of rain on the metropolis, which has forced the US Open authorities to plan for a Monday finish. Ian Ritchie, the chief executive of the All England Club, could not resist a chortle over the fact that it was the United States’s turn to contend with dire weather reports and prepare to toss their schedule into the air in the hope that someone would make sense of it.

For this is a championship that schedules doubles matches first on its prime show court on men’s quarter-finals day, stages exhibition games that are not part of the official programme, can never get a match started on time, has to wait until an NFL match is completed before its men’s final can start and, it is suggested, has allowed changeovers in matches to be extended as long as possible to sneak in a couple more commercials while players fret and foam. The US Open deserves a comeuppance and Hanna is ready to deliver.

For Murray, guaranteed to move up to No 4 when the next world rankings are released, Rafael Nadal, Roger Federer and Novak Djokovic – one of whom will lift the trophy tomorrow (or probably Monday) - the hanging around stokes up the tension as they reach fascinating and defining points in their careers. This is Murray’s chance to join the grand-slam set, Nadal hopes to become the first male in 39 years to win the French Open, Wimbledon and US Open in the same year, Federer is seeking a breakthrough in a year of illness and strife and Djokovic is desperate to prove that success in Australia in January was not a spectacular one-off.

What will we witness on the last day – Murray’s biceps, Nadal’s goal-scorer-like celebration, Federer’s beaming smile or Djokovic thumping his chest so hard that it is amazing he does not leave bruises? Murray is the new boy and he spoke before the tournament of his desire to “put myself in a position to win a grand-slam, and then we shall see if I’m ready”. There is little doubt in my mind that he is.

Lest one be accused of building up the 21-year-old to knock him over, he has come of age in the past four months. No one doubted that he had the game, he simply had to gather the experience, be content with his lot off court, get a few things off his chest in his first autobiography and then he would be set.

He has lost five times to Nadal, the world No 1, and most people expect a sixth defeat here. Murray does not. Of the four semi-finalists, he is in the best shape, when you factor in physical and mental condition. He has confirmed his qualification for the Masters Cup in Shanghai in November, so he knows that he can relax once the US Open and Great Britain’s Davis Cup tie against Austria in a fortnight are through, and he can give this weekend his all. For the others, the need to win may be too overwhelming.

“I sat down with Jez [Green, his physical trainer] at the start and told him not to let me get away with anything,” Murray said. “With Miles [Maclagan, his coach], if something isn’t right he had to tell me. We’ve all been straight with each other – this is a great experience for them as much as it is for me.” Now comes the wait.