Novak Djokovic's Players' Association Sued The Groups That Run Tennis. Why And What Do They Want?

Ons Jabeur is a three-time Grand Slam finalist with more than 13 million in prize money by age 30, and as she looked out at the main court used for the Miami Open this week and next, she rattled off a lengthy list of things she thinks could be fixed in professional tennis to help all players.

"We need to improve the structure that we have. ... We can do better about the scheduling. The times of matches. There are a lot of tournaments, and health-wise, for the players, I don't think that helps. The balls changing every week is not a good thing. Players deserve to be paid better," said Jabeur, a member of the executive committee of the Professional Tennis Players' Association , a group co-founded by Novak Djokovic several years ago. "Definitely a lot of things to work on."

Those issues Jabeur mentioned were among those raised in a class-action antitrust lawsuit filed by the PTPA in federal court in New York on Tuesday, calling the groups in charge of the sport - the women's WTA and men's ATP tours, the International Tennis Federation ITF and the agency that oversees anti-doping and anti-corruption efforts ITIA - a "cartel."

"The players really do demand to be heard, to have their issues taken seriously, to address these structural issues that plague tennis and really choke it as an international sport," said PTPA executive director Ahmad Nassar, "and to create a system that brings balance and equality and fairness to really the entire business of tennis."

Here is a look at the lawsuit - and there are similar actions moving forward in Brussels and London - and what it could mean for tennis: