Rafael Nadal's loss in the round of 16 at the US Open brings us a little closer to one of the biggest changes in the world of tennis. There is little time left for the great players of this era.

It is the first time since the 2003 US Open that we will not see Nadal, Federer, Djokovic (Big Three) or Serena Williams reach the quarterfinals of the championship. It seems that we are close to witnessing the retirement of these tennis legends.

It seems that Nadal and Djokovic intend to continue playing, while we are still waiting for an announcement from Federer. For her part, Serena Williams lost to Ajla Tomljanovic, and there are rumors that this was her last match as a professional.

None of the players who reached the quarterfinals of the US Open have won a Grand Slam, so we will have a new champion this year.