London - Novak Djokovic has warned tennis chiefs that their bitter feud over the Davis Cup and its new rival tournament will damage the sport.
Djokovic is frustrated with the ATP, who run the men's Tour, and the ITF, the governing body of world tennis, as they fight over the best way to use the 'team-based' competitions that have been overshadowed by the four Grand Slams.
The Davis Cup, run by the ITF, sees players represent their country each year, with four singles matches and one doubles rubber per tie in a tournament that culminates in a November final.
This year's title match sees France face Croatia next week, but the Davis Cup's profile remains low compared to Wimbledon and the Australian, French and US Opens.
The ITF have announced plans for a revamped 18-team Davis Cup, which would be held every November from 2019, after joining forces with an investment group led by Barcelona footballer Gerard Pique.
But the ATP responded by revealing earlier this year that they will launch a rival to the Davis Cup, called the World Team Cup, which will begin in the first week of January 2020.
The World Team Cup will take place in partnership with Tennis Australia and feature 24 teams, offering $14.78m in prize money.
World number one Djokovic is among a number of leading players baffled by the stand-off between the two organisations.
The 14-time major winner, who led Serbia to Davis Cup glory in 2010, believes having two such similar tournaments around the same time of year is unsustainable.
"Obviously the Davis Cup and World Team Cup situation is delicate. We find ourselves in this kind of particular circumstances and situations that we have to deal with right now," Djokovic told reporters at the ATP Finals on Wednesday.
"I think in the next two years we'll have both events happening in a very similar format if not the same, six weeks apart.
"Whether I think that's good for our sport? I honestly don't think it's good for the sport.
"More job opportunities for players, yes. But I think it's not sustainable. It will happen that we will have two average events."
Complicating the issue further, Djokovic also played in this year's edition of the Laver Cup, a tournament created by Roger Federer and his management team that features two teams made up of invited top players.
"Obviously Laver Cup is not an official competition. It doesn't have the points. But it has to be regarded as a very successful, very serious competition that attracts a lot of attention," Djokovic said.
"I watched it on TV last year. I was part of it this year. So far it's been the only competition that can actually get the biggest rivals in sport in one team. That was a very unique experience."
But Djokovic, a long-time member and president of the ATP Players council, admits the logjam of team events must end.
The 31-year-old hinted the sport's bosses may eventually come to the same realisation.
"I think creating one event is an ideal scenario and I think outcome for everyone," he said.
"From what I've heard from conversations with people from all of the sides, different sides in this sport, they all want to have one event because it's over-saturated with different cups, different events.
"We have the longest season in all sports. We're just adding events. We kind of have to try to focus on quality rather than quantity."