IF Andy Murray is to retain his US Open title, he must win six matches over the next 11 days.

He comfortably won his opening round at Flushing Meadows against Michael Llodra on Wednesday, but the task is about to become significantly harder over the next week or so. If all goes according to the seedings, the Scot will have to beat Tomas Berdych, Novak Djokovic and Rafael Nadal in succession from the quarter-finals onwards to lift the trophy in Arthur Ashe Stadium again this year.

For a male player to win a grand slam tournament, he must win 21 sets of tennis over the course of a fortnight, which is no mean feat. This is why there has been a discussion recently as to whether best-of-five sets matches are the best thing for the men's game. There is a persuasive argument that reducing men's grand slam tournament matches to best-of-three sets would be beneficial to both the players and the game as a whole.

The first reason to shorten the matches is to protect the players from the ever-increasing demands of the modern game. While a repeat of the record-breaking 11-hour, five-minute John Isner-Nicolas Mahut match at Wimbledon 2010 is unlikely, matches of that length are now relatively commonplace.

When you consider that elite marathon runners will compete only a few times a year due to the physical exertion that is required to run 26.2 miles, is it realistic to expect a tennis player to play five sets of tennis lasting five, or sometimes six hours, and then return just a couple of days later to do it all over again?

Wimbledon and the US Open are the only grand slam events this year in which the Big Four have all been present. Murray was absent from the French Open because of a back injury and Nadal missed the Australian Open as a result of the knee injury which forced him off the tour for eight months such was its severity.

While there is no definitive evidence that these injuries are as a consequence of five-set matches, there is little doubt that elite players today are being pushed to their physical limits like never before.

Such is the current strength-in-depth of men's tennis, winning a grand slam event can be a war of attrition as much as anything else. The eventual grand slam tournament winner can often be at the mercy of the draw; being in the toughest section of the draw can be fatal to any hopes of eventual victory. Djokovic played below his best in this year's Wimbledon final and, while he refuted the claim that his five-set semi-final victory against Juan Martin Del Potro - which lasted almost five hours - had left him fatigued, his performance perhaps suggested otherwise.

Another argument for shortening matches to best-of-three sets is purely on the basis of entertainment value. Five-setters can often turn into slugfests, with talent and finesse over-shadowed by pure athleticism. The best-of-three format lends itself to shorter, more intense matches with the London Olympics being the perfect example of this.

The format used in London 2012 was best-of-three sets throughout the tournament until the final, which was best-of-five.

Few people felt that the Olympic tournament lacked excitement as a result of this. John McEnroe supports the format deployed in London, saying: "I thought the dynamic of the best-of-three sets matches was good and the intensity level was higher, earlier [in the match]. Great as six-hour matches are, I think people would still watch them if they were three hours. Probably more people might watch them."

He makes a valid point.

Few people have the time or the will to watch a six-hour-long tennis match, so shortening matches could draw more fans in.

Traditionalists argue that changing the format of grand slam events to best-of-three sets would devalue these events, as the matches at the majors have always been contested over five sets.

Traditionally, though, there were no tie-breaks, meaning that sets of more than 20 games were a regular occurrence. There is little doubt that tie-breakers in the first four sets - and all five in the US Open - are good for the sport.

Support for the best-of-five format is widespread, though. Many claim that the increased physical demands are all part of the sport, with longer matches favouring the top players. This is true: over five sets, the better player usually wins. It is no coincidence that the fittest players on the circuit are also the best, and their superior conditioning and consistency prevails more often than not when it's best-of-five.

For the moment, then, the consensus among the players appears to be the status quo. For their individual wellbeing, and the heath of tennis in general, though, a change may be on the cards.