The fight for world No 1 between Roger Federer and Rafael Nadal is an old story, from the mid-2000s. The Swiss, who had spent a record 237 consecutive weeks as World No 1 was finally overtaken by the Spaniard in 2008, after a period of utter dominance and victory is what is now considered among the best Grand Slam finals ever, a historic Channel Slam beating Roger Federer at Wimbledon.

But almost a decade later, this race is still on. And in 2018, it has become a far more entertaining activity. The race has become musical chairs for the ATP World No 1 spot, and Federer and Nadal have exchanged the top spot six times in five months alone. From the time

Of the 22 weeks this year, Nadal has been world No 1 for 16 while Federer had held the position for 6.

What makes it even more remarkable is that Federer, the oldest ATP world No 1 in history, has skipped the entire clay-court season while Nadal, who became the oldest year-end world No 1 last year, was out injured for a good two months after withdrawing from his Australian Open quarter-final against Marin Cilic.

To make it even more complicated, Nadal had slipped down to number two despite his 11th French Open success after Federer won the Stuttgart Cup to bag the number one ranking for the sixth time and record 310th week, but this week Nadal is back above him by 50 points despite not playing since Roland Garros.

So why is it that a 36-year-old and 32-year-old have been the only two world No 1 despite the many anomalies in their season?

Tennis rankings are complex and depend on points gained in the last season and how they are defended in this season. Add to this the fact that the only other men to have challenged for the spot in over the decade – Novak Djokovic from 2011 and Andy Murray in 2016 – were injured and out of form and haven’t played enough.

By this yardstick, it is not odd to see the ranking change hands as often as it has since Federer has had a sub-par season compared to 2017. (Yes, it’s true.)

At this point last year, Federer already had won 4 titles – Australian Open (2000 points), Indian Wells and Miami Masters (1000 points each) and Halle (500 points.) This year, he has only defended one of these, the first Grand Slam in Melbourne. He lost the finals at both Indian Wells and Halle and lost in the first round in Miami.

However, he had won 2 ATP 250 titles this year – Rotterdam in February and Stuttgart in June. While the first gave him the chance to become the world No 1, the second gave him a chance to top Nadal, even though he had win the French Open.

However, his loss in the Halle final to Borna Coric on Sunday, means that Federer will be world No 2 heading into Wimbledon, but will still be the top seed.

Right now only 50 points separate them, but it is on the grass-court Grand Slam that the ranking scenario will get even more interesting. Nadal is defending only 180 points due to his Round of 16 loss in 2017, while defending champion Federer has 2000 points.

For the Swiss maestro who had spent 237 straight weeks at the top, the rankings might not count as much as another trophy. But for the tennis