Rafael Nadal's fitness will be crucial to Spain's hopes of winning the new-style Davis Cup competition ©Getty Images

Hosts Spain are favourites in the first of the controversial, new-style Davis Cup finals in Madrid this week.

The International Tennis Federation’s decision in 2018 to replace the 37-year-old format of home and away matches with a single, season-ending tournament involving 18 men’s teams was met with strong resistance.

Among the federations who opposed the change at the time were the Lawn Tennis Association, but they have since fallen into line behind the new ITF President David Haggerty, who took his landslide re-election in September as a sign that the changes he had backed were widely supported.

The 18 nations will play in six round-robin groups at La Caja Mágica, with winners advancing to the quarter-finals along with the two best runners-up.

The semi-finals will be held on Saturday (November 23), with the Davis Cup Final following on Sunday (November 24).

World number one Nadal, Novak Djokovic and Andy Murray are expected to feature for Spain, Serbia and Great Britain, respectively.

Belgium, featuring David Goffin, are in Group D along with Australia and Colombia.

Each tie will feature two singles matches and a doubles match, played across three sets.

Croatia are reigning champions after beating France in the 2018 final.

Serbia are waiting on the fitness of star player Novak Djokovic ©Getty Images
Serbia are waiting on the fitness of star player Novak Djokovic ©Getty Images

Assuming Nadal can maintain his recent form, having come through the Association of Tennis Professionals (ATP) Finals without exacerbating his recent abdominal injury, and fulfil his strong desire to represent his country, Spain are the favourites.

World number nine Roberto Bautista Agut is also on the Spanish team.

Serbia will assess the condition of Djokovic ahead of the tournament after his elimination from the ATP Finals, at which he suffered a recurrence of an elbow injury.

France, who have been drawn with Serbia in group A, feature Gaël Monfils, Benoit Paire and Jo-Wilfried Tsonga.

Murray, who led Britain to Davis Cup victory in 2015, will continue his road back from injury for Britain, who have a wildcard entry.

The Scot has expressed his delight at representing his country once again and told Sky Sports he believes Britain can progress from Group E, where they will play Kazakhstan and the Netherlands.

"I think we can get out of the group but it’s not a gimme for us,” he said. 

"There's so many good combinations in terms of the Kazakh singles and Dutch doubles so we'll need to play well to get through it."