No wonder Gerard Pique is nervous.

After years of trying to get his concept of a World Cup of tennis off the ground, the time has arrived, with the new-look Davis Cup finals beginning at Madrid's Caja Magica on Monday.

Having initially approached the ATP about the idea, Barcelona defender Pique and his Kosmos investment company went into partnership with the International Tennis Federation, taking the 120-year-old Davis Cup along for the ride.

Largely gone are the home and away ties with their fervent atmospheres but logistical headaches, to be replaced by a no-expense-spared week-long event that will undoubtedly be glitzy, but will it be a success?

To say not everyone in tennis is enthused would be a rather large understatement and, while Pique and Kosmos have met their first challenge by conjuring an impressive set-up to accommodate all the teams, bigger questions remain.

The new format, which will see 18 teams do battle in ties consisting of three best-of-three-sets matches, met with mixed reviews at the captains' press conferences on Sunday.

Australia's Lleyton Hewitt has been one of the most vocal critics having previously branded the changes "ridiculous".

Asked if he had been won over, Hewitt replied: "I still feel the same way. In terms of Davis Cup, that's how we all knew it.

"I make no secret that two of the biggest points of difference with Davis Cup and what the competition was about was home and away and best of five sets.

"But our boys get the chance to wear the green and gold and play for our country. It doesn't matter if we're playing marbles out there, we're going to go out and lay it all on the line. We just have to deal with the format as best as we possibly can."

Hewitt's scepticism is shared by Russia's veteran captain Shamil Tarpischev.

"It's going to be my 93rd Davis Cup tie as a team captain so I would say I'm an advocate of traditions," he said.

"We were playing previously five-setters, now we're playing three-setters. It's a bit like comparing classic chess versus speed chess.

"It's an interesting format for the top players, it's also interesting for the countries who are hosting this event, but I still think that we should have further discussion about this format down the road."

Croatia are the defending champions having defeated France in Lille a year ago. With all the semi-finalists from the previous year earning direct entry to the finals, they have not had the chance to play in front of their home fans.

Franko Skugor, the stand-in captain following the sudden departure of Zeljko Krajan last week, said: "It's a different feeling, definitely.

"That was the main part of the spirit of Davis Cup, to play at home in front of your home crowd. We in Croatia only have one small ATP tournament, we don't have a big event to be able to play in front of our people."

Nostalgia for the old Davis Cup is inevitable but in reality the competition had been losing its lustre for a number of years, with the leading players increasingly choosing not to participate and revenue from sponsorship and TV rights dwindling.

Pique and Kosmos still have work to do on the latter but the field is generally impressive despite the absence of Roger Federer and Alexander Zverev and the withdrawals of Daniil Medvedev, Marin Cilic and Kei Nishikori.

The impression so far is that this format is good for the players – although its position so late in the calendar is far from ideal – but not for fans.

Spain's two group contests are the only sell-outs of the 25 ties and several matches are likely to be played in front of sparse crowds.

A lack of atmosphere must be Pique's chief concern, with critics ready to jump on any negativity.

That will not be a concern for Spain, whose team includes Rafael Nadal and their captain Sergi Bruguera.

He said: "I like the new format very much. It's good that we have more possibility that the top players can play and I think the organisation is very good for all the teams. We feel the support. It's a little bit of an advantage for us."

The stakes for Pique, a long-time tennis fan, have been further raised, meanwhile, by the looming presence of the ATP Cup just six weeks away.

Having decided not to partner with Pique, the ATP formed its own, similar competition and scheduled it for the start of next season.

Whether both can succeed, or even survive, is very much in question.

Novak Djokovic, who is playing Davis Cup for Serbia for the first time in two-and-a-half years and will also play in the ATP Cup, has his doubts.

The world number two said: "There was some change very much needed for the team competitions to gain more attention, more significance. Whether the format change is going to help this competition and elevate it to a different level, I don't know.

"Maybe because of the differences they (Davis Cup and ATP Cup) can coexist but there's a lot of players that share the same opinion that the time between the two tournaments is too short and it's going to be really hard for both of these big team competitions to thrive."

History is the Davis Cup's trump card and Pique hopes this week will prove he can put the competition back at the forefront of tennis.

"We understand we have to start little by little," he said on daviscup.com. "In five years' time, I want everyone, players and fans, to think 'Davis Cup is in November and I want to be there'."