Albert Costa, who won the Davis Cup for Spain three times, as player and captain, hopes tradition will be enough to stave off opposition to the radical changes engulfing the 118-year-old competition but predicts a merger with the ATP’s rival World Cup in the next two years could ultimately settle the conflict.

“We know that one form of the Davis Cup is finished, and one is going to come,” Costa told the Guardian on Wednesday, looking back on the last of the old finals – in Lille at the weekend, when Croatia beat France 3-1 – and forward to the experiment he will oversee as tournament director in Madrid next November.

Novak Djokovic fears for Davis Cup as rival event crowds tennis calendar Read more

“At the end of the day, everybody wanted a change, and [the investment company] Kosmos and [Barcelona footballer and Kosmos president] Gerard [Piqué] did it. It is very good for everybody, especially for the players, for the fans. The feelings, of course, are mixed but the new competition is going to be much better than the old one.”

Meanwhile, the world No 1, Novak Djokovic – who will boycott Madrid – made Costa’s task significantly more complicated when it was revealed he is campaigning to scrap the rule that players can only be eligible for the Olympics if they play in the Davis Cup. If the leading players do not need to play in Madrid in November to play in Tokyo the following July, their already firm attachment to the 10-day ATP World Cup in Melbourne in January 2020 will be hugely strengthened.

Costa concedes the ATP’s new event has merit, but counters: “It is not the official tournament for countries. I know it is similar to the new Davis Cup final, but it is a completely different thing. [With the] Davis Cup, you are playing for your country and your federation is behind you, public opinion is behind you, your government is behind you, everybody is behind you. You feel that pressure, and that is what makes the Davis Cup so important.

Facebook Twitter Pinterest Albert Costa lifts the Davis Cup trophy as captain in 2011. Photograph: Javier Diaz/Reuters

“ With a new competition, you don’t feel like this. I played before in the World Team Cup in Düsseldorf, which was something similar – although this is going to be bigger – and I never felt like I did when I was playing Davis Cup.”

Pierre-Hugues Herbert, the French doubles specialist, echoed Djokovic’s cynicism in stronger terms in Lille at the weekend. “We hope the new format will not work and we will come back to the old one,” he said. “When we left the stadium, we took a photo of this moment because we don’t know if it will be repeated.” He had the moral support of his losing teammate, Lucas Pouille – and a majority of the crowd, judging by their sporadic booing of ITF officials.

Almost daily developments suggest the power play between the ITF boss, David Haggerty, and his ATP counterpart, Chris Kermode, could be resolved in 2020 but Costa is not as purblind as some to the vigour of the opposition, and agrees there probably will be a merger for a unified world team competition, including the WTA.

“That’s a reality,” he says. “Everybody is talking, and I think it’s an open door to make a mixed competition, and to do it together. That’s what my information is. At the end of the day, I think it will be best for all of tennis, but we’ll see how it goes. We have two years to try to convince the ATP and the tennis world that maybe two competitions are not good for any of us.”

If there is to be an amicable resolution to an argument everyone but those in a position to avoid it could see, it will take the calm counsel of former players such as Costa to ease the way, because he understands both sides of the argument. He hears the players’ complaints about the timing of the final, for instance – just six weeks before the ATP event.

“I can understand the players’ point,” he says, “but the reality is right now, if they are in the final, they have to play Davis Cup at that time anyway. It’s better now because you only have to play two weeks to have the chance to win the Davis Cup. Before you had to play four weeks, and over five sets. Your efforts were greater. Now, six countries only have to play one week, and the other 12 play only two weeks.”

Quick guide Changes to the Davis Cup from 2019 Show Hide • The new Davis Cup will culminate in a season-ending, 18-team tournament at a neutral venue in November that the ITF hopes will be more attractive to elite players. • Countries can progress to the final from a 24-team qualifying round in February made up of home and away ties. The 12 winners advance; the losers are relegated to Group 1 and play ties in April/September. • Davis Cup semi-finalists from the previous year will join the 12 qualified nations at the November finals, along with two wildcards. • The November finals feature six three-team groups in a round-robin format, with two singles matches and one doubles match per tie. Matches are best-of-three-sets. • Group winners advance to single elimination quarter-finals. The two best second-placed teams join them. • The four teams to win their quarter-final qualify for the following year. Ethan Van Ristell Photograph: Pascal Rossignol/X00234

Costa admits he will probably miss the old format – which is so precious to traditionalists and romantics. “That is only human. But the thing is, I would have loved to have this new competition. When I was a player, we were already asking [the ITF] to change things. Now it’s done and I think it’s going to be much better for everybody: for the players, for the fans, for the TV, for the press. We will do it for the first time, and then the world will see how it works, how good the competition is.”

He says he has his longtime friend and old doubles partner, Rafael Nadal, on board, although he is unsure of some of the other big hitters. And it’s still a gamble, right? “Right now, maybe. At the moment, it doesn’t exist. We have to show people what it is going to be like, then maybe we can form an opinion. Right now we can talk. I can’t imagine how it’s going to be – and I love the idea. We have to show it to the world.”