Roger Federer can stake an irresistible claim to being the greatest tennis player of all-time with a watershed victory in the French Open starting on Sunday.
Exactly where, though, will the Swiss master rank if he falls short once again in Paris?
More specifically, where can Federer expect to be placed among the legends of the game if Rafael Nadal buries him in the red dirt of Roland Garros for a fifth straight year?
Debate has raged over Federer's standing in history since 2004 when he dominated his peers like no player in 20 years.
First he moved past his childhood idols Edberg and Becker on the grand slam leaderboard.
Then McEnroe, Lendl, Connors, Rosewall and Agassi.
It was all a blur as, in the space of four heady years, Federer reeled in, then eclipsed the sport's most revered names Perry, Tilden, Borg, Laver and Emerson.
Tennis with a wand, they called it, as Federer mesmerised opponents with a mix of elegance, skill and ruthlessness not seen before.
He rewrote the record books over and over, reaching an unprecedented 12 major finals in succession and reigning as world No1 for 237 consecutive weeks.
As he sauntered towards Pete Sampras's 14 slams, it no longer seemed a race, merely a matter of time before he set a new benchmark.
Getting there before Tiger Woods won more golf majors than Jack Nicklaus's 18 appeared the greater challenge.
But, as injuries took their toll, his relentless pursuit slowed to a relative shuffle, Federer taking another full year an age by his freakish standards to reach 13.
The tears of joy that followed his emotional Australian Open triumph in front of Laver and in the presence of the family of his late former coach, Australian Peter Carter, turned to tears of despair as Nadal denied him for the third straight time in a grand slam final in this year's Melbourne Park decider.
''Look, I love this game. It means the world to me, so it hurts when you lose,'' Federer explained.
To many, though, the defeat which followed his straight-sets humbling at the hands of Nadal in Paris seven months earlier and agonising five-set loss to the Spaniard at Wimbledon cut much deeper than that.
It was as though Federer had come to the grim realisation that his quest to catch Sampras may have been coming to an end.
The Swiss maestro had been two tantalising points away from retaining the trophy at the All England Club, while it also took Nadal five enthralling sets the first Open final to go the distance in 21 years to thwart Federer in Melbourne.
Reverse the two results and it would have been a case of job done for Federer a record 15 majors in the bag and tennis immortality assured, even if a French Open remained forever out of his reach.
If only it were that simple.
The harsh reality for Federer is that Nadal's twin successes on grass and hard courts heralded the coronation of a new tennis king.
In levelling their career series on hard courts at 3-3 and snapping Federer's five-year, 65-match winning streak on grass after losses in the two previous Wimbledon finals Nadal had emphatically confirmed the shift in power.
In doing so the Spaniard also appeared to fracture Federer's confidence.
On the surface Federer now looked to have no answers to Nadal's unyielding defence, indomitable will and left-handed power game no matter where they stoushed.
Federer, though, insisted that was never the case after ending his seven-month title drought and Nadal's 33-match winning run on clay in the Madrid Masters final last Sunday.
''It's not like a relief. I was so close to him at Melbourne and Wimbledon. But I always kept the belief that I could beat him again,'' he said.
''That's what you need on this kind of surface. I stayed positive.''
Staying positive on clay looked an impossibility after Nadal humiliated Federer for the loss of just four games in a 2008 French Open final mismatch.
With the two tennis titans once again seeded and on form to clash in this year's title match in a fortnight's time, debate over Federer's standing in history will inevitably intensify.
A Federer breakthrough, giving the 27-year-old a grand slam set and drawing him level with Sampras, would end all arguments. Statistically Federer would be regarded as the world's finest player.
The most vexing questions would arise from another second-best showing from Federer in Paris.
The most convenient answer would be that, no, Federer could not be regarded as the greatest unless he completed his grand slam resume.
In truth, it is far more complex than that.
It is not inconceivable to suggest Nadal still just 22 might win a dozen or so titles in Paris, where he is yet to lose on four visits, if he doesn't go weak at the knees.
He has trumped Federer in the past three finals, plus the semi-final in 2005.
While short-sighted neutrals claim Federer is no dirt force, the Swiss superstar rightly contends that clay is anything but his Kryptonite.
''I don't think the clay has been my problem. My problem has been Rafa on clay. That's a big difference,'' Federer said.
''I grew up on clay and have played well on clay a lot if you look at my record of the last few years. If he hadn't been there, we would be talking differently today.''
In fact, had Nadal not been there it would be Federer with four French Open crowns the equal second-most along with 1920s and '30s Frenchman Henri Cochet.
It would be Federer not Nadal challenging Bjorn Borg's record six titles at Roland Garros.
With 17 slams, there would be no debate.
But would'ves, should'ves and could'ves have never counted when taking on history.
Federer is the only man who can settle the argument with a victory, particularly the sweetest one possible over Nadal, in the French capital on June 7.
Even if he were to never taste success in Paris, with a swag of runner-up finishes at Roland Garros, Federer could claim to be the second-best on clay and boast the numbers elsewhere to make him the greatest.
Until, of course, Nadal completes his own grand slam collection at the US Open.
Then we will have another debate altogether. AAP