Bill Elliott, Prostate Cancer UK ambassador and Golf Monthly editor-at-large, tells us about a now-famous two horse race as we head into the final major golf tournament of the year in Carolina, and explains why Quail Hollow golf course is more than a little tricky to play.
On the face of it, it's silly to reduce the small army of competitors in the year's final Major to just two protagonists.
Silly but inevitable, as we wend our way towards Quail Hollow in Carolina and the supporters of Jordan Spieth and Rory McIlroy continue their arguments over which of these two young superstars is the outstanding leader of today's gilded brat-pack.
Each now has the chance of becoming only the seventh player in the game's history to complete the Grand Slam of Masters, US Open, The Open and the USPGA.
It is this last title that is up for grabs this week, and though it has long been the runt of this particular litter - lacking both the glamour and the prestige of the other three - it is, for this week at least, truly glittering.
There is also a dramatic contrast in style between the 24 year old American and the 28 year old Northern Irishman.
Where Spieth is all about strategy, calmness and an impeccable putting stroke, McIlroy is centred on flair and exuberance.
If each plays to his maximum this weekend, the smart money would edge its way towards McIlroy.
The big races, however, do not always go to the swiftest, even if that remains the better way to bet. While McIlroy embraces all that panache, it is the strength of Spieth's mind that has taken him to the highest levels.
While McIlroy occasionally appears to lose a bit of heart, Spieth often seems to grow stronger in the face of adversity on the inevitable bad days in a game that is more contrary than any other.
It is this contrast in style and demeanour that offers fans the opportunity to enjoy both.
Each man appears to be (a) ludicrously rich and (b) relatively grounded. Each is now even more motivated by the other's success.
McIlroy, surely, is the more ignited here: until Spieth's dramatic emergence two years ago, it seemed stitched on that he was destined to dominate for years to come - even if domination in golf means no more than occasional success on the biggest weeks.
What we know also is that McIlroy loves Quail Hollow and its challenges. He has won twice here already, while Spieth has played the course only once and finished a mediocre 30-something.
No wonder McIlroy says he is looking forward to it, because "when you've been successful on a course, and you know you can play it well, then obviously it adds a bit of confidence".
On the other hand, Spieth is riding a big wave in 2017, with two PGA victories already - plus that extraordinary win at The Open last month, when he sprinted away from the edge of self-implosion to finally erase the memory of last year's collapse at Augusta.
Who will win? As ever, who knows - this early interest in this pair may well have evaporated by the halfway point as others stake their own claim to the most unattractive prize in golf: the Wanamaker Trophy, an over-sized cup that requires the sort of mantelpiece usually only found in a castle.
Leading this other pack is Japan's latest hero, Hideki Matsuyama, whose blistering form in last week's World Championship events confirmed his high position among the game's elite posse.
What is certain is that Quail Hollow offers a three-hole finish so tough you have to look to Scotland and the minefield that is Carnoustie's climax to find anything comparable.
The 16th is a 510 yard par 4, the 17th a 223 yard par 3 and the 18th another long par 4. Each has water embracing it somewhere, each offers more disaster than triumph, each will test the nerve of whoever arrives there next Sunday with a chance of missing.
They call this final stretch The Green Mile, but 'Barbed Wire Alley' would be a more accurate description of a collection of holes that may change everything. Watch it - it should be fun for those of us on the sidelines.
Prostate Cancer UK ambassador