There is a race for the year-end world number one ranking in the men’s game both unforeseen and memorable – tennis fans will be discussing long into the future.

Rewind 12 months. After holding all four slams simultaneously Novak Djokovic loses his Wimbledon title (3rd round defeat to Querrey) to Andy Murray. Murray then goes on a rampage in the second half of the year, with Djokovic's form waning post completion of his grand slam set, and overturns the successful Serb as the new world number one. It has taken Andy Murray until the age of twenty-nine and it’s a pleasant and thoroughly deserved development. Nobody could argue that he hadn't battled and earned that standing atop the world rankings. 

In those final months of 2016, both Rafael Nadal and Roger Federer had been out of action nursing various injuries and it had started to look like age was catching up to the two legends of the era. 

For over a decade it was those four men (The Big Four) who had won almost every grand slam. It was a spectacular hold that they had had at the top of the men's game. But something was changing and it felt like another generation was also getting ready to break through (the young NextGen players, not to mention Kyrgios and Thiem among others). In an era this successful, great to watch and dynamic, nobody knew what lay ahead, and only a brave man would've safely predicted it. 

However, if in 2016 at any point anyone had suggested to Djokovic, Murray and the rest of the tennis world that 2017 would see Roger and Rafa battling it out once again for the year end world number one and with a grip on all three of the year's slams, with only the US Open remaining, well, they might have been surprised, shocked even, and that goes for the general public and everyone associated with tennis too. They might've thought you'd lost your mind and were on a nostalgia trip taking you back a decade in time. After all, Federer hadn't won a slam since Wimbledon 2012 (coming close several times), and Nadal not since the Roland Garros title in 2014. Both men had seemed to have periods of lower confidence and their games had suffered and both men had seen a slip in the rankings. Neither man, however, had seemed to lose that fire in their belly; neither man had ever looked hungrier for titles. 

Roger and Rafa might have cheekily said “well, why not?” They, themselves might have been surprised at the prospect, while both believing in their own abilities and passion meant anything was possible and perhaps such a moment to take advantage of would come their way. 

And here we are. The likely event is that Roger Federer, reborn since his January 2017 return from injury, or his friend and nemesis, Rafael Nadal, also in some of the best form of his life in the aftermath of a three-month stint on the sidelines with his own injury in late 2016, will claim the 2017 year-end world number one spot. The question on everyone's lips right now relates to who it’s going to be. 

Looking at the number 1 position, Andy Murray can likely do very little to defend that spot, as his considerably poor 2017 continues (injuries just one of the reasons for the start-stop campaign) and his huge amount of points to defend make it a seemingly impossible task. 

Novak Djokovic has pulled the plug on his 2017 campaign and will end the season at his lowest ranking in years.

Others who might've been there or thereabouts are having a poor year - Nishikori, Raonic, and Wawrinka, who is doing his own thing measured beside nobody else - in this era who can blame him? Alex Zverev is being truly impatient in his bid for tennis supremacy and will have to learn a little patience is necessary at a time when the best players are still considerably better than he is. 

So, after dreaming about it for years, as Djokovic and Murray came to the forefront, it's finally here… we do have Roger versus Rafa again. In what seems like the umpteenth part of the greatest sporting rivalry of modern times (somehow even more special as they are friends who greatly respect one another) there will be a chapter that 2017 is long remembered for. Is it a swan song for the rivalry? It does start to seem hard to believe this could sustain itself long beyond this calendar year as the younglings are crackling with drive and big ambition. But the gulf between the others and Roger and Rafa's games this year is still huge. There have been a few close moments, such as Nadal against the younger Zverev at the Australian Open, but those are the kind of matches these top players live for, especially Nadal.

So, who is it going to be? Roger has by far the most impressive record this year, with only two losses to his name. Rafa has played some of his best tennis on hard courts for some years though and even looked handy at Wimbledon on the grass. That was until the near unstoppable Muller did what many players love to do at Wimbledon and put Nadal out and on the next flight back to Mallorca, thereby depriving us of a possible Roger versus Rafa reunion at Wimbledon. Cilic played a great tournament, but very few wouldn't have wanted to see a repeat of the Australian Open final again. 

Both men are in fine form. The time machine they've used together is working well. While neither would begrudge the other the number one ranking again, both men will inevitably have their eyes fixed on what would be a remarkable achievement. Nadal with the slightly stronger year so far (let us not forget that Federer took the entire clay court season off in preparation to win Wimbledon again) may return to the pinnacle in the coming months to have Roger beat him to that spot at the year’s end. It's a fascinating predicament for the final months of the year in the men's game and shows unreservedly that these two legends may be as fine as we are ever going to see in the sport, for so many reasons.

Post-Wimbledon, the two men who have succeeded in qualifying for the Nitto ATP Finals in London so far are Nadal (7,095  points) and Federer (6,545  points), of course. Thiem is their closest rival in the third spot, and he is more than 3,000  points behind Federer, to underscore just how far the two stalwarts are ahead at this point in the year. Federer is narrowly behind Nadal in second place and has played two months fewer of the tour, which is something worth remembering. The US Open winner will get 2,000  points, as at the other grand slam events, and there are four remaining Masters tournaments (in Montreal, Cincinnati, Shanghai, and Paris) still to come, with each a chance for the winner to take 1,000  points, as well as the showdown in London for the ATP finals, in which a total of 1,500  points is the maximum possible to take away. Barring injuries, it is likely to be a two-horse race.

Roger’s break during the clay court season was a masterstroke. That said, he has announced he will take no further breaks this season and the imminent American swing leading up to the US Open and ending at the Nitto ATP Finals in November will show us if he can continue what he has done thus far this year, over a slightly more sustained period. Nadal has slogged away hard and is probably a little more tired, so that period could really test his fitness. Let’s hope that both men stay in shape so we get a race that will cap off a wonderful year of men’s tennis. I personally think that Roger will make it, but don’t be surprised if Rafa is there or thereabouts, or even gets back to the pinnacle of their sport before the year’s end, only to then be bumped. Either way, the next few months represent fascinating viewing and who could fail to be both excited and awestruck. 2017 is a year men’s tennis will never ever forget.