The Croatian team celebrating their Davis Cup victory. (AP Photo)

For over 100 years, the Davis Cup, outside of the Olympics, has been the premier tournament for ATP players wanting to represent their country. In August, the ITF voted on sweeping changes to the Davis Cup, many of which have caused considerable controversy among the tour.

Tomas Berdych went so far as to say that the changes would be "the death of the event," and Lucas Pouille insists he will never play the new Davis Cup while former world No. 1 Lleyton Hewitt called the changes a "disgrace." Yeah, some players are not happy. Even Roger Federer believes that, while the Davis Cup needed to be reformatted, the new rules are not the answer.

The new rules will be enforced in 2019, which means that Croatia is the last team to win the old Davis Cup format when they beat France last month. 

What are the changes that have been so controversial? See for yourself: