Last week Novak Djokovic won his third consecutive ATP World Tour Finals title whilst also in the process securing the World Number One ranking for the year. Apart from a minor (and temporary) blip against Japanese player Kei Nishikori in the semi-final, Djokovic swept aside all those in his way with disdain.

The same could be said of his opponent in the final. Roger Federer mercilessly destroyed his opponents in the round robin, including British hope Andy Murray 6-0 6-1, before squeaking past compatriot Stanislas Wawrinka in the semi-final.

But then disaster struck, as Federer was forced to pull out of the final with a back injury. As a result, London was denied the match that it had patiently waited a week for. This does raise a pertinent question. Given the one-sided nature of almost all the other matches in the tournament, has what was traditionally called the ‘Big Four’ now become a ‘Big Two’?

For those of you who don’t know, tennis’ traditional ‘Big Four’ did consist of Novak Djokovic, Roger Federer, Rafael Nadal and Andy Murray. However, in the last year Andy Murray has fallen down the rankings (although this could arguably be attributed to the back surgery that he opted to have late last year).

Having said that, Andy Murray had won three of the five tournaments he played in in the weeks leading up to the final showdown. But that form was nowhere to be seen once he entered the arena for his match with Roger Federer. Federer dispatched Murray in just 56 minutes. A crowd of 16,000 watched in shock as a traditionally close match became painfully embarrassing for the former World Number Two. It capped a tough year for Murray, as he failed to win a single match against Federer, Djokovic and Nadal.

Some would say that it is harsh on Rafael Nadal to say that he can no longer be included in the very top bracket of players. The case for Nadal is strengthened when it is considered that he reached the final of the Australian Open, where he lost to Wawrinka (although he did suffer an injury during the match), and won the French Open. But the statistics since the Roland Garros do not make pretty reading for Nadal. He has not made a final since Paris in May, let alone win a tournament. This should be qualified with the fact that he was absent from the US Open and the ATP World Tour Finals with injury.

But would that actually have made a difference?

Since winning the US Open in 2013, Nadal has only beaten Djokovic once – in the French Open Final this year. He was even beaten by Djokovic on clay in Rome, a tournament he was won seven times in the last ten years. Andy Murray’s stats against Djokovic and Federer are even less favourable. Murray hasn’t beaten Federer since January 2013, and hasn’t won a set against him since January this year. Against Djokovic, Murray hasn’t won since his fabled triumph at Wimbledon in 2013. He won a set against him at the US Open this year, but that remains his only set since that game at Wimbledon.

But what about the chasing pack? Have Stanislas Wawrinka, or Kei Nishikori (the two semi-finalists from last week) bridged the gap enough to be considered genuine contenders against the might of Federer and Djokovic? The statistics suggest that they haven’t yet. Wawrinka pushed Federer close last week, but Nishikori struggled against him. Wawrinka was mercilessly destroyed by Djokovic in a haphazard performance last Wednesday.

Their head to head records also seem to agree with this. Wawrinka has only beaten Djokovic once since 2006, whilst he has only toppled Federer twice in his career. Both matches were on clay as well, easily Federer’s worst surface. Nishikori’s record against Federer and Djokovic is slightly more favourable, as he is only behind 3-2 on a head to head with each of them.

The bottom line? Through some of the others are injured, Djokovic and Federer do seem to have pulled away from the pack. Whether Nadal and Murray can catch them back up will depend on how they recover. Wawrinka and Nishikori would appear to be nearest to Djokovic and Federer at the moment.

The tennis world will be hoping that these two can bridge the gap before Federer retires, as otherwise we may be faced with a ‘Big Two’ becoming just the ‘Big One’.