WE’VE been here once before of course, but this time it feels very different.

When Andy Murray walks onto the court for Sunday’s Australian Open final, which – and some of you will be able to confirm this depending on when you’re doing your reading – is almost certain to be against Roger Federer, he will not be the nervous, callow youth that appeared at Flushing Meadow for the final of the 2008 US Open.

Instead, he will emerge as a fully-fledged British sporting icon who believes, justifiably, his time has come.

Everything he has trained, prepared and devoted himself towards has been geared to reach its apogee at this moment. History awaits, and in a glorious contrast to this country’s perennially-penned tale of gallant yet futile sporting failure, Murray has proved himself capable of crossing the line. A 74-year wait for a British male Grand Slam winner might just have two more days to run.

But why the confidence, given British tennis’ seemingly symbiotic relationship with false expectations?

Why the belief that Murray will succeed where Tim Henman and Greg Rusedski failed?

Because, and the events of the last two weeks have only served to reinforce this, Murray has assumed the aura of a winner rather than a nearly-man.

Clearly, sporting success at the highest level demands skill, technique, strength and mental clarity.

But sometimes, all of those things are not enough.

Henman boasted plenty of wonderful attributes, but he never came across as a figure who was destined to win things. Rafael Nadal, on the other hand, was an obvious winner from the moment he burst on to the scene. He lacked the grace and style of many of his contemporaries, but you knew from the moment you first saw him holding his racket that he would still end his career as a champion.

He had, for want of a better phrase, the X-Factor.

The sporting author Simon Barnes has discussed it extensively, and it might best be described as greatness, a force of character, presence and performance that trumps all other quantifiable measures of ability.

You can’t measure it on a Pro Zone print out, but at the most significant of sporting moments, it knocks all other attributes into a cocked hat.

Sir Steve Redgrave clearly had it, and that’s why even when an Olympic final was slipping out of his reach, there was never any real likelihood of him finishing anywhere other than the top of the podium.

It’s what separates the good from the truly great, and while it tends to be most prevalent in individual sports, it can also be encountered in a team setting.

Martin Johnson had it, as did Eric Cantona. Whatever else was happening, you just knew they would find a way of coming out on top.

Federer has exuded greatness for more than a decade, and while there have been hiccups along the way, most notably against Nadal, the Swiss has constantly reasserted his position at the very top of the tree.

For a number of years, Murray needed that final, all-powerful constituent to complement the other attributes he so obviously possessed.

He burst onto the senior circuit with an all-court game as good as anything around, but was too uncertain, too flighty, to translate his talent into a Grand Slam success.

He has stood on the brink of glory on a number of occasions, but he was never great enough to convert them into wins. Until, that is, now.

The Murray that has swept all before him at Melbourne Park this month is a completely different animal to the player who has wilted in the past.

In the early rounds, he swatted inferior opponents with something approaching disdain. In the quarterfinals, against a Nadal who, although eventually forced to retire, played some sublime tennis in the opening two sets, he carried the air of a winner throughout.

And yesterday, at the semi-final stage, he refused to allow some early adversity to deflect him from the path he believes is his destiny.

Trailing by a set and defending a break point in his opening service game of set two, Murray was faced with a defining ‘here-we-go again’ moment. The good player tries his best, but fails to establish a winning position.

The great player, however, retains his serve without ever giving any indication the outcome was in doubt.

Murray did exactly that and never looked back as he secured an ultimately comfortable four-set triumph.

He will need to draw on that same sense of pre-destiny on Sunday because, if it is to be Federer he faces, you can rely on the world number one doing the same.